Gem Enhancements and Care

Gemstones have been enhanced through various methods for hundreds of years. Even the prettiest stones can come out of the ground looking like average rocks, but with a lapidary's skillful cutting and, sometimes, the application of enhancements like simple heat or more advanced procedures, their beauty is revealed.

While some stones like peridot and various garnets are usually not enhanced, many others are sometimes, regularly, or even always enhanced. Those enhancements are common, accepted, and even expected in the industry. Enhancements also help determine how to best care for your gemstones. The chart below lists our gemstones with the known possible enhancement methods for each stone.

gemstone/species (a)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
abalone (shell)	3 - 4	no treatment	n/a	n/a	n/a	Abalone is very soft, so be mindful of scratching. Avoid sudden temperature changes, chemicals, and ultrasonic cleaners. In addition to above precautions: avoid perfumes, and hairsprays. Requires gentle handling.
abalone (shell)	3 - 4	dyed	to add color	commonly	good
abalone pearl (pearl)	2.5 - 4	no treatment	n/a	n/a	n/a	Abalone is very soft, so be mindful of scratching. Avoid sudden temperature changes, chemicals, and ultrasonic cleaners. In addition to above precautions: avoid perfumes, and hairsprays. Requires gentle handling.
abalone pearl (pearl)	2.5 - 4	dyed	to add color	commonly	good
adularia (orthoclase feldspar)	6 - 6.5	not known to be treated	n/a	n/a	n/a	Normal care
agate (quartz)	6.5	no treatment	n/a	n/a	n/a	Normal care
agate (quartz)	6.5	dyed/stained/bleached	to alter color	commonly	good to excellent	Normal care
albite	6 - 6.5	not known to be treated	n/a	n/a	n/a	Normal care
alexandrite (chrysoberyl)	8.5	not known to be treated	n/a	n/a	n/a	Normal care
alexandrite, synthetic (lab created)	8.5	not known to be treated	n/a	n/a	n/a	Normal care
almandite (garnet)	7 - 7.5	not known to be treated	n/a	n/a	n/a	Normal care
amazonite (microcline feldspar)	6.5	no treatment	n/a	n/a	n/a	Avoid hard wear, heat, chemicals and ultrasonic cleaners.
	6.5	heated	to improve color	unknown	very good
	6.5	impregnated with colorless wax or oil	to improve overall appearance and luster	unknown	good to fair
	6.5	impregnated with hardening agents or plastic	to improve appearance and durability	usually	very good
amber/copal green	2 - 2.5	heated	to create color	always	good to very good	Amber is very soft, so be mindful of scratching. Avoid abrasives, ultrasonic, solvents and heat. Requires gentle handling.
amber/copal carved natural color doublet	2 - 2.5	assembled	for contrast	occasionally	good
amber/copal red	2 - 2.5	dyed	to alter color	commonly	good to very good	Amber is very soft, so be mindful of scratching. Avoid abrasives, ultrasonic, solvents and heat. Requires gentle handling.
amber/copal red	2 - 2.5	heated	to alter color	usually	good to very good
amber/copal yellow, golden brown	2 - 2.5	no treatment	n/a	n/a	n/a	Amber is very soft, so be mindful of scratching. Avoid abrasives, ultrasonic, solvents and heat. Requires gentle handling.
	2 - 2.5	heated to create sun spangles	to improve appearance, deepen color, add spangles	commonly	good to very good
	2 - 2.5	dyed/stained	to alter color	rarely	variable
amber/copal doublet all colors	2 - 2.5	assembled	to alter color	occasionally	good	Amber is very soft, so be mindful of scratching. Avoid abrasives, ultrasonic, solvents and heat. Requires gentle handling.
pressed amber/copal yellow, golden brown	2 - 2.5	heated oils and pressure	to fuse and shape smaller pieces	commonly	good to very good	Amber is very soft, so be mindful of scratching. Avoid abrasives, ultrasonic, solvents and heat. Requires gentle handling.
pressed amber/copal red	2 - 2.5	heated oils and pressure	to fuse and shape smaller pieces	commonly	good to very good	Amber is very soft, so be mindful of scratching. Avoid abrasives, ultrasonic, solvents and heat. Requires gentle handling.
amblygonite, (Montebrasite) yellow and colorless	6	not known to be treated	n/a	n/a	n/a	Gentle wear, can be brittle.
amblygonite blue, green, yellow	6	irradiated	to alter color	usually	*Research in progress	Gentle wear, can be brittle.
amethyst (quartz)	7	no treatment	n/a	n/a	n/a	Avoid extreme heat, avoid jewelers torch.
amethyst (quartz)	7	heated/irradiated	to improve color	occasionally	excellent	Avoid extreme heat, avoid jewelers torch.
ametrine (quartz)	7	no treatment	n/a	n/a	n/a	Avoid extreme heat, avoid jeweler's torch.
ametrine (quartz)	7	heated	to improve color	often	excellent	Avoid extreme heat, avoid jeweler's torch.
ammolite shell doublet	3.5 - 4	assembled	to improve durability	usually	fair to good	Ammolite is very soft, so be mindful of scratching. Avoid abrasives, ultrasonic, solvents and heat. Requires gentle handling.
ammolite shell triplet	8	assembled	to improve durability	usually	excellent	Ammolite is very soft, so be mindful of scratching. Avoid abrasives, ultrasonic, solvents and heat. Requires gentle handling.
andalusite	7 - 7.5	no treatment	n/a	n/a	n/a	Normal care
andalusite	7 - 7.5	heated	to improve color	occasionally	excellent	Normal care
andesine-labradorite (plagioclase feldspar) red, green	6 - 6.5	heated/diffused	to alter color	commonly	** Research in progress	Normal care
andesine-larbradorite yellow (plagioclase feldspar)	6 - 6.5	not known to be treated	n/a	n/a	n/a	Normal care
andradite (garnet)	6.5	no treatment	n/a	n/a	n/a	Normal care
andradite (garnet)	6.5	low temperature heat	to improve color	often	excellent	Normal care
apatite	5	no treatment	n/a	n/a	n/a	Apatite is moderately soft, so be mindful of scratching. Avoid ultrasonic cleaners.
apatite	5	heated	to improve color	usually	good
apatite cat's-eye	5	no treatment	n/a	n/a	*Research in progress	Apatite is moderately soft, so be mindful of scratching. Avoid ultrasonic cleaners.
apatite cat's-eye	5	heated	to improve color	often	good
aquamarine (beryl)	7.5 - 8	no treatment	n/a	n/a	n/a	Normal care
aquamarine (beryl)	7.5 - 8	heated	to improve color	almost always	excellent	Normal care
aragonite all colors	3.5 - 4	no treatment	n/a	n/a	n/a	Aragonite is very soft, so be mindful of scratching. Avoid abrasives, ultrasonic, solvents and heat. Aragonite is generally unsuitable for jewelry.
	3.5 - 4	dyed	to alter color	sometimes	fair to good
	3.5 - 4	waxed/oiled	to improve color	sometimes	fair to good
aventurine (quartzite)	6.5	no treatment	n/a	n/a	n/a	Normal care
aventurine (quartzite)	6.5	dyed	to improve color	often	good to excellent	Avoid abrasives, ultrasonic, solvents and heat.
azurite	3.5 - 4	no treatment	n/a	n/a	n/a	Azurite is very soft, so be mindful of scratching. Avoid abrasives, ultrasonic, solvents and heat. Azurite is generally unsuitable for jewelry.
	3.5 - 4	coated	to improve appearance and durability	occasionally	fair to good
	3.5 - 4	filled with oil/resin and polymer	to stabilize and improve appearance	occasionally	good
azurmalachite	3.5 - 4	no treatment	n/a	n/a	n/a	Azurmalachite is very soft, so be mindful of scratching/breaking. Avoid abrasives, ultrasonic, solvents and heat.
	3.5 - 4	impregnated	to improve appearance and durability	rarely	fair to good
	3.5 - 4	filled with oil/resin and polymer	to improve appearance and durability	rarely	good
azurmalachite (specimen)	3.5 - 4	not known to be treated	n/a	n/a	n/a	Azurmalachite is very soft, so be mindful of scratching/breaking. Avoid abrasives, ultrasonic, solvents and heat.
	3.5 - 4	impregnated	to improve appearance and durability	rarely	fair to good
	3.5 - 4	filled with oil/resin and polymer	to improve appearance and durability
gemstone/species (b)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
banded agate (quartz)	6.5	dyed/stained	to alter color	commonly	excellent	Avoid harsh chemicals, acetone and ultrasonic cleaners. Can be affected by perspiration.
bastnaesite	4 - 4.5	not known to be treated	n/a	n/a	n/a	Gentle wear, moderately soft and brittle. Not suitable for jewelry.
benitoite	6.5	not known to be treated	n/a	n/a	n/a	Normal Care
bixbite, red beryl (beryl)	7.5 - 8	oiled/resin infused	to improve clarity and appearance	commonly	fair to good, may require maintenance	Avoid ultrasonic cleaners, and harsh chemicals.
goshenite, colorless beryl (beryl)	7.5 - 8	not known to be treated	n/a	n/a	n/a	Normal Care
green beryl	7.5 - 8	not known to be treated	n/a	n/a	n/a	Normal Care
yellow beryl	7.5 - 8	not known to be treated	n/a	n/a	n/a	Normal Care
yellow beryl	7.5 - 8	irradiated	to produce color	usually	variable	Normal Care, but some stones may fade in prolonged exposure to light or heat.
black onyx (quartz)	6.5	dyed/stained	to alter color	always	good to excellent	Normal Care
bloodstone (quartz)	6 - 6.5	not known to be treated	n/a	n/a	n/a	Normal Care
bone/ivory	2 - 3	bleached	to improve color	commonly	good	Bone and ivory are very soft and may discolor with time. Discoloration is due to porosity/absorption of body oils or other substances from wearing. Be mindful of scratching. Avoid chemicals and ultrasonic cleaners. Requires gentle handling.
	2 - 3	dyed/stained	to alter color	occasionally	good
	2 - 3	impregnated	to minimize porosity	occasionally	good
gemstone/species (c)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
carnelian/sard (quartz)	6.5	heated	to improve color	usually	excellent	Normal Care
	6.5	dyed/stained	to alter color	occasionally	good to excellent	Avoid harsh chemicals, acetone and ultrasonic cleaners. Can be affected by perspiration.
	6.5	impregnated	to minimize porosity	occasionally	good
cerussite	3.5	not known to be treated	n/a	n/a	n/a	Very gentle care; not suitable for jewelry.
chalcedony (quartz)	6.5	no treatment	n/a	n/a	n/a	Normal care
chalcedony (quartz)	6.5	dyed/stained	to alter color	usually	good to excellent	Avoid harsh chemicals, acetone and ultrasonic cleaners. Can be affected by perspiration.
blue chalcedony (quartz)	6.5	no treatment	n/a	n/a	n/a	Normal Care
blue chalcedony (quartz)	6.5	dyed/stained	to alter color	commonly	fair to good	Avoid harsh chemicals, acetone and ultrasonic cleaners. Can be affected by perspiration.
chalcedony blue, green (quartz)	6.5	irradiated	to alter color	commonly	fair to good	Avoid abrasives, ultrasonic, solvents and heat. Some stones may fade in light or heat.
chalcedony green (quartz)	6.5	dyed/stained	to alter color	almost always	excellent	Avoid harsh chemicals, acetone and ultrasonic cleaners. Can be affected by perspiration.
chrome diopside	5.5	not known to be treated	n/a	n/a	n/a	Chrome diopside is moderately soft, so be mindful of scratching. Avoid abrasives and solvents.
cat's-eye chrysoberyl (chrysoberyl)	8.5	no treatment	n/a	n/a	n/a	Normal care
cat's-eye chrysoberyl (chrysoberyl)	8.5	heated	to improve color	occasionally	excellent	Normal care
brown, yellow, green chrysoberyl (chrysoberyl)	8.5	irradiated	to create color	occasionally	excellent	Normal care
brown, yellow, green chrysoberyl (chrysoberyl)	8.5	heated	to improve color	occasionally	excellent	Normal care
chrysocolla	2 - 4	not known to be treated	n/a	n/a	n/a	Chrysocolla is very soft, so be mindful of scratching. Requires gentle handling.
chrysoprase (quartz)	6.5	not known to be treated	n/a	n/a	n/a	Normal care
citrine (quartz)	7	no treatment	n/a	n/a	n/a	Normal care
	7	heated	to alter color	usually	excellent	Normal care
	7	irradiated	to create color	sometimes	excellent	Normal care
citrine madeira (quartz)	7	no treatment	n/a	n/a	n/a	Normal care
citrine madeira (quartz)	7	heated	to alter color	usually	excellent	Normal care
lemon citrine. ouro verde (quartz)	7	irradiated	to create color	always	excellent	Normal care
clinohumite	6	not known to be treated	n/a	n/a	n/a	Requires gentle handling.
black coral (coral)	3	not known to be treated	n/a	n/a	n/a	Avoid ultrasonic cleaners and extreme heat. Treat gently due to softness of the coral.
blue coral (coral)	3	dyed/stained	to improve color and texture	commonly	good	Avoid ultrasonic cleaners and extreme heat. Treat gently due to softness of the coral.
	3	impregnated with colorless wax or oil	to improve texture	commonly	good
	3	impregnated with plastic	to improve texture	commonly	very good
golden coral (coral)	3	bleached	to lighten color from black	almost always	very good	Avoid ultrasonic cleaners and extreme heat. Treat gently due to softness of the coral.
orange coral (coral)	3 - 4	no treatment	n/a	n/a	n/a	Avoid ultrasonic cleaners and extreme heat. Treat gently due to softness of the coral.
	3 - 4	stabilized	to improve durability	commonly	very good
	3 - 4	dyed/stained	to alter color	commonly	good
	3 - 4	impregnated waxed/oiled	to improve appearance and luster	commonly	good
pink coral (coral)	3 - 4	not known to be treated	n/a	n/a	n/a	Avoid ultrasonic cleaners and extreme heat. Treat gently due to softness of the coral.
	3 - 4	impregnated waxed/oiled	to improve appearance and luster	commonly	good
	3 - 4	dyed/stained	to alter color	commonly	good
red coral (coral)	3 - 4	dyed/waxed	to improve color and texture	commonly	good	Avoid ultrasonic cleaners and extreme heat. Treat gently due to softness of the coral.
	3 - 4	impregnated with colorless wax or oil	to improve quality of material for shaping and polishing	commonly	good
	3 - 4	impregnated with plastic	to improve quality of material for shaping and polishing	commonly	very good
sponge coral (coral)	3	no treatment	n/a	n/a	n/a	Avoid ultrasonic cleaners and extreme heat. Treat gently due to softness of the coral.
	3	dyed	to alter color	commonly	good
	3	impregnated with plastic	to improve quality of material for shaping and polishing	commonly	very good
white coral (coral)	3 - 4	no treatment	n/a	n/a	n/a	Avoid ultrasonic cleaners and extreme heat. Treat gently due to softness of the coral.
	3 - 4	enhanced/bleached	to alter color	commonly	good
	3 - 4	impregnated waxed/oiled	to improve appearance and luster	commonly	good
cubic zirconia (lab created)	8 - 8.5	lab created	n/a	n/a	n/a	Normal care
cubic zirconia (lab created)	8 - 8.5	CVD coated	to add or minimize color	rarely	poor to good	Color may be affected by polishing, recutting, ultrasonic cleaners, alcohol, and harsh chemicals.
gemstone/species (d)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
danburite	7 - 7.5	no treatment	n/a	n/a	n/a	Normal care
	7 - 7.5	heated	to alter color	unknown	excellent	Normal care
	7 - 7.5	irradiated	to create color	commonly	good	Avoid temperature changes, steaming, chemicals, and ultrasonic cleaners.
dendritic agate (quartz)	6.5	not known to be treated	n/a	n/a	n/a	Normal care
diamond colorless normal color range D-F and near-colorless normal color range G-J	10	no treatment	n/a	n/a	n/a	Normal care
	10	HPHT (high pressure,high temperature)	to lighten or change color	to lighten or change color	excellent	Normal care
	10	lasered	to improve clarity	often	very good	Normal care
	10	fracture filled	to improve clarity	occasionally	fair to very good	Avoid extreme heat, temperature changes, steaming, chemicals and ultrasonic cleaners.Avoid jeweler's torch and recutting.
	10	CVD coated	to add or minimize color	rarely	poor to good	Color may be affected by polishing, recutting, ultrasonic cleaners, alcohol, and harsh chemicals.
diamond colored	10	HPHT (high pressure,high temperature)	to improve color	occasional - increasingly common	excellent	Normal care
	10	lasered	to improve clarity	occasionally	very good	Normal care
	10	irradiated	to create color	often	very good to excellent	Normal care
	10	fracture filled	to improve clarity	sometimes	fair to very good	Avoid extreme heat, temperature changes, steaming, chemicals and ultrasonic cleaners. Avoid jeweler's torch and recutting.
	10	CVD coated	to add color	sometimes	poor to good	Color may be affected by polishing, recutting, ultrasonic cleaners, alcohol, and harsh chemicals.
diamond fancy colored	10	not known to be treated	n/a	n/a	n/a	Normal care
diaspore	6.5 - 7	not known to be treated	n/a	n/a	n/a	Normal care
diopside	5.5	not known to be treated	n/a	n/a	n/a	Diopside is moderately soft, so be mindful of scratching.
Shanseres (diopside)	5.5	not known to be treated	n/a	n/a	n/a	Diopside is moderately soft, so be mindful of scratching.
drusy quartz (quartz)	7	no treatment	n/a	n/a	n/a	Normal care
	7	dyed	to alter color	commonly	good to very good	Avoid polishing, heat, temperature changes, steaming, chemicals and ultrasonic cleaners.
	7	plated	to apply a metallic coating	commonly	very good	Avoid polishing, heat, temperature changes, steaming, chemicals and ultrasonic cleaners.
gemstone/species (e)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
emerald (beryl)	7.5 - 8	no treatment	n/a	n/a	n/a	Normal care
	7.5 - 8	dyed/stained	to alter color	occasionally	variable	Avoid extreme heat, temperature changes, steaming, chemicals and ultrasonic cleaners.
	7.5 - 8	fracture filled with oil/resin	to improve clarity and appearance	usually	fair to good; may require maintenance	Avoid extreme heat, temperature changes, steaming, chemicals and ultrasonic cleaners. Avoid jeweler's torch and recutting.
	7.5 - 8, possibly lower	fracture filled w/ hardened resin	to improve clarity and appearance	sometimes	fair to good	Avoid extreme heat, temperature changes, steaming, chemicals and ultrasonic cleaners. Avoid jeweler's torch and recutting.
	7.5 - 8, possibly lower	ExCel™	to improve clarity and appearance	sometimes	good	Normal Care
enstatite	5.5	not known to be treated	n/a	n/a	n/a	Enstatite is moderately soft, so be mindful of scratching. Requires gentle handling.
euclase	7.5	not known to be treated	n/a	n/a	n/a	Brittle; not suitable for jewelry.
gemstone/species (f)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
fire agate (chalcedony)	6.5	not known to be treated	n/a	n/a	n/a	Normal care
fire opal (opal)	5.5 - 6	no treatment	n/a	n/a	n/a	Avoid water, heat and solvents. Fire Opal is moderately soft, so be mindful of scratching. Normal, gentle handling.
	5.5 - 6	impregnated	to improve appearance	commonly	good
	5.5 - 6	dyed/stained	to add color	commonly	good
fire opal boulder (opal)	5.5 - 6	no treatment	n/a	n/a	n/a	Avoid water, heat and solvents. Fire Opal is moderately soft, so be mindful of scratching. Normal, gentle handling.
fire opal boulder (opal)	5.5 - 6	host material may be dyed/stained	to improve appearance	sometimes	good to very good
fluorite	4	no treatment	n/a	n/a	n/a	Very soft stone, requires gentle handling.
	4	heated	to improve appearance	unknown	fair to good
	4	irradiated	to create color	unknown	fair to good
gemstone/species (g)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
color change garnet (garnet)	7 - 7.5	not known to be treated	n/a	n/a	n/a	Normal care
malaya/malaia garnet (garnet)	7 - 7.5	not known to be treated	n/a	n/a	n/a	Normal care
mali garnet (garnet)	7 - 7.5	not known to be treated	n/a	n/a	n/a	Normal care
mint garnet (garnet)	7 - 7.5	not known to be treated	n/a	n/a	n/a	Normal care
Mozambique garnet (garnet)	7 - 7.5	not known to be treated	n/a	n/a	n/a	Normal care
pink garnet (garnet)	7 - 7.5	not known to be treated	n/a	n/a	n/a	Normal care
topazolite garnet (garnet)	7 - 7.5	not known to be treated	n/a	n/a	n/a	Normal care
gemstone/species (h)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
hauyne	6	not known to be treated	n/a	n/a	n/a	Normal, gentle handling.
helenite (lab created)	5 - 5.5	lab created	n/a	n/a	n/a	Normal, gentle handling.
heliodor yellow (beryl)	7.5 - 8	irradiated	to improve color	almost always	good	Normal care
hematite	5.5 - 6.5	not known to be treated	n/a	n/a	n/a	Normal care
hessonite/imperial (garnet)	7 - 7.5	not known to be treated	n/a	n/a	n/a	Normal care
hiddenite green (spodumene)	6.5 - 7	no treatment	n/a	n/a	n/a	Normal care
hiddenite green (spodumene)	6.5 - 7	irradiated	to create color	rarely	poor	Gentle care. Avoid prolonged exposure to bright light and heat to prevent color fading.
howlite white (quartzite)	3 - 3.5	not known to be treated	n/a	n/a	n/a	Howlite is very soft, so be mindful of scratching. Avoid harsh chemicals, ultrasonic cleaners, and steaming.
howlite other colors (quartzite)	3 - 3.5	dyed/stained	to add color	commonly	good to very good	Howlite is very soft, so be mindful of scratching. Avoid harsh chemicals, ultrasonic cleaners, and steaming.
gemstone/species (i)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
indicolite (tourmaline)	7 - 7.5	no treatment	n/a	n/a	n/a	Normal care
	7 - 7.5	heated	to improve color	commonly	excellent	Normal care
	7 - 7.5	oiled/resin infused	to improve appearance	occasionally	fair to good	Avoid steaming, harsh chemicals, ultrasonic, and temperature changes.
iolite (cordierite)	7 - 7.5	not known to be treated	n/a	n/a	n/a	Normal care
mammoth ivory (ivory)	2 - 3	impregnated/bleached	to improve appearance	commonly	good	Mammoth ivory is very soft and may discolor with time. Discoloration is due to porosity/absorption of body oils or other substances from wearing. Be mindful of scratching. Avoid chemicals and ultrasonic cleaners. Requires gentle handling.
gemstone/species (j)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
jade all colors (jadeite)	6.5 - 7	no treatment	n/a	n/a	n/a	Normal care
	6.5 - 7	waxed/oiled	to improve appearance	commonly	good	Avoid heat, harsh chemicals, and ultrasonic cleaners.
	6.5 - 7	bleached/impregnated (B-Jade)	to improve appearance	often	good	Avoid heat, harsh chemicals, and ultrasonic cleaners.
	6.5 - 7	dyed/stained	to add color	often	good	Avoid strong light, chemicals, and ultrasonic cleaners.
jade (nephrite)	6 - 6.5	no treatment	n/a	n/a	n/a	Normal care
jade (nephrite)	6 - 6.5	dyed/stained	to add color	rarely	unknown	Avoid strong light, harsh chemicals, and ultrasonic cleaners. Discoloration may occur with time.
jade (goldenite)	6.5 - 7	dyed/layered gold leaf/stabilized	n/a	always	good	Avoid strong light, chemicals, and ultrasonic cleaners.
jasper (quartz)	6 - 6.5	no treatment	n/a	n/a	n/a	Avoid chemicals, steam, and ultrasonic cleaners.
jasper (quartz)	6 - 6.5	dyed	to add color	occasionally	fair to good	Avoid chemicals, steam, and ultrasonic cleaners.
jeremejevite	6.5 - 7.5	not known to be treated	n/a	n/a	n/a	Normal care
gemstone/species (k)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
kornerupine	6.5	not known to be treated	n/a	n/a	n/a	*Research in progress
kunzite pink, violet (spodumene)	6.5 - 7	no treatment	n/a	n/a	n/a	Gentle care. Exposure to ultraviolet light will cause slow fading. Avoid ultrasonic cleaners.
	6.5 - 7	irradiated	to improve color	commonly	fair
	6.5 -7	heated	to improve color	commonly	fair
kyanite	5 and 7	not known to be treated	n/a	n/a	n/a	Moderately soft and brittle, so be mindful of scratching.
gemstone/species (l)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
labradorite spectrolite (plagioclase feldaspar)	6 - 6.5	not known to be treated	n/a	n/a	n/a	Normal, gentle handling.
labradorite yellow (plagioclase feldspar)	6 - 6.5	not known to be treated	n/a	n/a	n/a	Normal, gentle handling.
lapis lazuli	5 - 6	no treatment	n/a	n/a	n/a	Normal care
	5 - 6	waxed/oiled	to improve appearance	commonly	fair	Avoid chemicals and ultrasonic cleaners.
	5 - 6	heated/dyed/stained	to improve color	commonly	variable
	5 - 6	impregnated with plastic or other hardening agent	to improve durability and appearance	rarely	good
lazulite	5 - 6	not known to be treated	n/a	n/a	n/a	Avoid strong light, chemicals, and ultrasonic cleaners.
lepidolite	2.5	not known to be treated	n/a	n/a	n/a	Lepidolite is very soft, so be mindful of scratching. Requires gentle handling.
larimar	4.5 - 5	not known to be treated	n/a	n/a	n/a	Normal care
gemstone/species (m)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
magnesite	4	not known to be treated	n/a	n/a	n/a	Gentle care; not suitable for jewelry.
malachite	3.5 - 4	no treatment	n/a	n/a	n/a	Malachite is very soft, so be mindful of scratching. Avoid chemicals and ultrasonic cleaners.
	3.5 - 4	coated with colorless wax	to improve appearance	occasionally	fair
	3.5 - 4	impregnated with plastic or other hardening agents	to improve appearance and durability	rarely	good
	3.5 - 4	dyed	to improve color uniformity	occasionally	good
marcasite (pyrite)	6 - 6.5	not known to be treated	n/a	n/a	n/a	Normal care
maw sit-sit	6 - 6.5	not known to be treated	n/a	n/a	n/a	Normal care
Maxixe blue beryl (beryl)	7.5 - 8	irradiated	to create the blue color	always	poor	Maxixe beryl is very special. Avoid prolonged exposure to light and heat to avoid quick fading of color.
moldavite (natural glass)	5.5	not known to be treated	n/a	n/a	n/a	Normal care
moonstone (orthoclase feldspar)	6 - 6.5	not known to be treated	n/a	n/a	n/a	Normal care
morganite pink, peach (beryl)	6 - 6.5	no treatment	n/a	n/a	n/a	Normal care
	7.5 - 8	heated	to improve color	commonly	excellent
	7.5 - 8	irradiated	to produce color	commonly	excellent
moss agate (quartz)	6.5	not known to be treated	n/a	n/a	n/a	Normal care
mother of pearl (shell)	3	no treatment	n/a	n/a	n/a	Mother of pearl is very soft and porous, so avoid heat, chemicals, and ultrasonic cleaners.
mother of pearl (shell)	3	dyed/stained	to alter color	commonly	good to very good
muscovite	2.5	not known to be treated	n/a	n/a	n/a	Muscovite is very soft, so be mindful of scratching. Requires gentle handling.
gemstone/species (o)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
obsidian (natural volcanic glass)	5 - 5.5	not known to be treated	n/a	n/a	n/a	Avoid repolishing, heat, chemicals, and ultrasonic cleaners.
boulder opal (opal)	6	no treatment	n/a	n/a	n/a	Normal care
boulder opal (opal)	6	oiled/resin infused	to improve appearance and clarity	occasionally	fair	Avoid heat, chemicals, ultrasonic, and repolishing.
cat's-eye opal (opal)	6	impregnated	to improve appearance and durability	usually	good	Avoid heat, chemicals, and ultrasonic cleaners.
doublet opal (opal)	6	assembled product	to improve color and/or durability	always	good	Avoid heat, chemicals, ultrasonic, and repolishing.
matrix opal (opal)	6 or possibly less	dyed/stained	to darken color	commonly	good	Avoid heat, solvents, and repolishing.
mosaic opal (opal)	6 or possibly less	assembled product	to create opal effect from smaller stones	commonly	good	Avoid heat, solvents, and repolishing.
peruvian opal (opal)	6 - 6.5	not known to be treated	n/a	n/a	n/a	Avoid heat, chemicals, and ultrasonic chemicals.
synthetic opal (lab created opal)	5.5 - 6	lab created	n/a	n/a	n/a	Normal care
triplet opal (opal)	6 or better	assembled product	to improve color and/or durability	always	fair to good	Avoid heat, solvents, chemicals, ultrasonic, and repolishing.
white, crystal, black, semi-black opal (opal)	6	no treament	n/a	n/a	n/a	Avoid excessive heat, solvents, and ultrasonic cleaners.
	6	impregnated, oiled/resin infused	to improve appearance	rarely	fair
	6	coated	to improve color	occasionally	fair to good
	6	inlaid opal	to improve color	often	good
gemstone/species (p)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
cultured pearl freshwater and saltwater (akoya pearl)	3 - 4	no treatment	n/a	n/a	n/a	Avoid cosmetics, perfumes, hairsprays, and household chemicals.
	3 - 4	bleached	to whiten and remove discoloration	usually	excellent
	3 - 4	dyed/stained	to add color	commonly	good
	3 - 4	dyed/stained, potential colored nuclei	to add color	occasionally	variable
	3 - 4	irradiated	to create color	occasionally	very good
	3 - 4	coated	to even color and improve luster	often - increasingly common	fair to good
cultured Tahitian pearl (pearl)	3 - 4	no treatment	n/a	n/a	n/a	Avoid cosmetics, perfumes, hairsprays, and household chemicals.
cultured Tahitian pearl (pearl)	3 - 4	dyed	to add color	commonly	good
mabe pearl (pearl)	3 - 4	ASSEMBLED PRODUCT: coated, dyed, bleached, filled w/hardened substance + a mother-of-pearl back.	to improve color and durability	always	fair to very good	Avoid cosmetics, perfumes, hairsprays, and household chemicals.
natural pearl (pearl) very rare	3 - 4	bleached	to whiten and remove discoloration	usually	very good	Avoid cosmetics, perfumes, hairsprays, and household chemicals.
natural pearl (pearl) very rare	3 - 4	dyed/stained with or without heat	to alter color	rarely	good to very good
peridot (olivine)	6.5	no treatment	n/a	n/a	n/a	Avoid ultrasonic cleaners.
	6.5	impregnated, oiled/waxed	to improve appearance	rarely	fair to good	Avoid sudden temperature changes, harsh chemicals, and ultrasonic cleaners.
	6.5	filled	to improve clarity	rarely	good
petalite	6 - 6.5	not known to be treated	n/a	n/a	n/a	Avoid rough handling, ultrasonic cleaners.
petrified wood (quartz)	6.5	no treatment	n/a	n/a	n/a	Normal care
	6.5	bleached	to remove color	occasionally	good
	6.5	heated	to improve color	occasionally	good
pezzotaite	8	not known to be treated	n/a	n/a	n/a	Normal care
phenakite	7.5 - 8	not known to be treated	n/a	n/a	n/a	Normal care, but avoid sudden temperature changes.
pietersite (quartz)	6.5	not known to be treated	n/a	n/a	n/a	Normal care
pietersite Henanite (quartz)	6.5	not known to be treated	n/a	n/a	n/a	Normal care
plagioclase (feldspar)	6 - 6.5	not known to be treated	n/a	n/a	n/a	Avoid heat, chemicals, steam, ultrasonic cleaners.
prasiolite (quartz)	7	irradiated/ annealed	to alter color	almost always	very good	Normal care
prehnite	6	n/a	n/a	n/a	n/a	Normal, gentle handling.
pyrite	6 - 6.5	not known to be treated	n/a	n/a	n/a	Avoid harsh chemicals and excessive heat.
pyrope garnet (garnet)	7 - 7.5	not known to be treated	n/a	n/a	n/a	Normal care
gemstone/species (q)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
blue moon quartz (quartz)	7	heated	to create effect	usually	excellent	Normal care
cat's-eye quartz (quartz)	6.5	no treatment	n/a	n/a	n/a	Normal care
cat's-eye quartz (quartz)	6.5	heated	to alter color	usually	excellent	Normal care
dumortierite quartz (quartz)	6.5	oiling	to reduce appearance of natural fissures	usually	excellent	Normal care
hawk's-eye, blue tiger's eye quartz (quartz)	6.5	no treatment	n/a	n/a	n/a	Normal care
	6.5	heated	to alter color	usually	excellent
	6.5	chemical bleaching with acid or bleaching agents	to alter color	usually	excellent
latte quartz (quartz)	7	irradiated/heated	to alter color	usually	excellent	Normal care
lazulated quartz (quartz)	7	not known to be treated	n/a	n/a	n/a	Normal care
lilac quartz (quartz)	7	heated	to improve color	occasionally	excellent	Normal care
mystic quartz (quartz)	7	coated with titanium	to produce mystic quartz	usually	very good	Normal care but chipping may reveal natural color, so avoid abrasions and recutting.
quartz w/special inclusions (lepidocrocite, medusa, leopard, strawberry) (quartz)	7	not known to be treated	n/a	n/a	n/a	Normal Care. While they are a 7 in hardness, a proliferation of inclusions may alter this, either strengthening or weakening a material.
quenched cracked and dyed quartz (quartz)	7	heated/cooled, dyed	to add color and inclusions	commonly	fair to good	Avoid heat, temperature changes, steaming, chemicals, ultrasonic cleaners, and repolishing.
quenched cracked and dyed quartz (quartz)	7	dyed	to add color and inclusions	commonly	poor to very good (depending on dye used)
rhodizite	8	not known to be treated	n/a	n/a	n/a	Normal care
rhyolite (igneous rock)		not known to be treated	n/a	n/a	n/a	Normal care
rock, colorless quartz (quartz)	7	not known to be treated	n/a	n/a	n/a	Normal care
rose quartz (quartz)	7	no treatment	n/a	n/a	n/a	Normal care
rose quartz (quartz)	7	dyed	to improve color	commonly	good to very good	Avoid temperature changes, steaming, chemicals, and ultrasonic cleaners.
rutilated quartz (quartz)	7	not known to be treated	n/a	n/a	n/a	Normal care
smoky quartz (quartz)	7	irradiated	to create color	usually	good	Normal care
tourmalinated quartz (quartz)	7	not known to be treated	n/a	n/a	n/a	Normal care
quartzite	6 - 6.5	no treatment	n/a	n/a	n/a	Normal care
	6 - 6.5	dyed	to alter color	commonly	excellent
	6 - 6.5	impregnated with colorless plastic	to improve appearance and durability	commonly	good
gemstone/species (r)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
rhodochrosite	3.5 - 4	not known to be treated	n/a	n/a	n/a	Normal care
rhodolite (garnet)	7 - 7.5	not known to be treated	n/a	n/a	n/a	Normal care
rhodonite	5.5 - 6	no treatment	n/a	n/a	n/a	Normal care
rhodonite	5.5 - 6	dyed/stained	to add color	occasionally	poor	Avoid chemicals and ultrasonic cleaners.
rock crystal quartz (quartz)	7	not known to be treated	n/a	n/a	n/a	Normal care
ruby (corundum)	9	no treatment	n/a	n/a	n/a	Normal care
	9	heated	to improve color and clarity	usually	excellent
	9	filled/flux healed	to improve clarity	occasionally	excellent
	9	Beryllium lattice diffusion	to improve color	occasionally	excellent
	9 or possibly lower	filled/lead glass	to improve clarity	commonly	poor	Avoid common household chemicals, steam cleaners, and ultrasonic cleaners. Avoid jewelers torches.
	9	surface diffusion	to improve color	occasionally	good	Avoid repolishing/recutting and scratching.
	9	dyed/stained	to alter color	rarely	poor	Avoid harsh chemicals and ultrasonic cleaners.
star ruby red, pink, purple (corundum)	9	no treatment	n/a	n/a	n/a	Avoid jeweler's torches; otherwise normal care.
	9 or possibly lower	lead glass filled	to improve clarity; fill cracks	rarely	fair	Avoid common household chemicals, steam cleaners, and ultrasonic cleaners.
	9	surface diffusion	to impant star	occasionally	excellent	Avoid jeweler's torches; otherwise normal care.
	9	heated	to improve color	sometimes	excellent	Avoid jeweler's torches; otherwise normal care.
star ruby Indian plum (corundum)	9	no treatment	n/a	n/a	n/a	Avoid jeweler's torches; otherwise normal care.
star ruby Indian plum (corundum)	9 or possibly lower	lead glass filled	to improve clarity/fill surface pits and cracks	sometimes	fair	Avoid common household chemicals, steam cleaners, and ultrasonic cleaners.
ruby zoisite	6.5 - 7	not known to be treated	n/a	n/a	n/a	Normal care
gemstone/species (s)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
sapphirine	7.5	not known to be treated	n/a	n/a	n/a	Normal care
blue sapphire (corundum)	9	no treatment	n/a	n/a	n/a	Avoid jeweler's torches; otherwise normal care.
	9	heated	to improve color and clarity	usually	excellent	Normal care
	9	beryllium lattice diffusion	to lighten color	occasionally	excellent	Normal care
	9 or possibly lower	filled + lead glass	to add color and improve clarity	rarely	fair to poor	Avoid common household chemicals, steam cleaners, and ultrasonic cleaners.
fancy sapphire green, orange, purple, pink, padparadscha, yellow (corundum)	9	no treatment	n/a	n/a	n/a	Avoid jeweler's torches; otherwise normal care.
	9	heated	to improve color and clarity	usually	excellent	Normal care
	9 or possibly lower	filled/lead glass	to improve clarity	commonly	poor	Avoid common household chemicals, steam cleaners, and ultrasonic cleaners.
	9	beryllium lattice diffusion	to improve color	commonly	excellent	Normal care
star sapphire blue (corundum)	9	no treatment	n/a	n/a	n/a	Avoid jeweler's torches; otherwise normal care.
	9	heated	to improve color	sometimes	excellent	Avoid jeweler's torches; otherwise normal care.
	9	surface diffusion	to impant star	often	excellent	Avoid repolishing/recutting,scratching and jeweler's torches.
star sapphire gray, white (corundum)	9	no treatment	n/a	n/a	n/a	Avoid jeweler's torches; otherwise normal care.
star sapphire gray, white (corundum)	9	surface diffusion	to impant star	occasionally	excellent	Avoid repolishing/recutting,scratching and jeweler's torches.
star sapphire black (corundum)	9	no treatment	n/a	n/a	n/a	Normal care
	9	coating	to prevent flaking	often	excellent	Avoid solvents and ultrasonic cleaners.
	9 or possibly lower	lead glass filled	reduce appearance of cracks	sometimes	fair to poor	Avoid common household chemicals, steam cleaners and ultrasonic cleaners.
scapolite yellow	5.5 - 6	not known to be treated	n/a	n/a	n/a	Normal, gentle handling.
scapolite violet	5.5 - 6	no treatment	n/a	n/a	n/a	Normal, gentle handling.
scapolite violet	5.5 - 6	heated	to produce color	rarely	good	Normal, gentle handling.
scheelite	4.5 - 5	not known to be treated	n/a	n/a	n/a	Gentle care; not suitable for jewelry.
serpentine	2.5 - 5.5	no treatmentd	n/a	n/a	n/a	Serpentine is very soft, so be mindful of scratching Avoid sudden temperature changes, chemicals, and ultrasonic cleaners. Requires gentle handling.
	2.5 - 5.5	dyed/stained	to alter color	commonly	fair to good
	2.5 - 5.5	impregnated, waxed/oiled	to improve hardness and luster	commonly	good to very good
shell tortoise, oyster, paua	3 - 4	dyed/stained	to alter color	commonly	fair to good	Shell is very soft, so be mindful of scratching. Avoid ultrasonic, chemicals, and solvents. Requires gentle handling.
sillimanite	7.5	not known to be treated	n/a	n/a	n/a	Normal care
sillimanite, cat's eye	6 - 7	not known to be treated	n/a	n/a	n/a	Normal, gentle handling.
sinhalite	6.5	not known to be treated	n/a	n/a	n/a	*research in progress
sodalite	5.5 - 6	no treatment	n/a	n/a	n/a	Normal care
sodalite	5.5 - 6	dyed/stained	to alter color	sometimes	fair	Special care required as dye may fade.
spessartite/ mandarin garnet (garnet)	7 - 7.5	not known to be treated	n/a	n/a	n/a	Normal care
sphene	5 - 5.5	no treatment	n/a	n/a	n/a	Require no special care, but is best suited for earrings and pendants due to its moderate softness.
sphene	5 - 5.5	heated	to created red or orange color	rarely	fair to good
sphalerite	3.5 - 4	not known to be treated	n/a	n/a	n/a	Sphalerite is a very soft stone, so be mindful of scratching. It is generally not suitable for jewelry.
spinel	8	not known to be treated	n/a	n/a	n/a	Normal care
spodumene yellow (Terador™)	6.5 - 7	no treatment	n/a	n/a	n/a	Normal, gentle handling.
spodumene yellow (Terador™)	6.5 - 7	irradiated	to create color	rarely	poor	Gentle care. Color fades in strong light/sunlight. Avoid ultrasonic cleaners.
stronium titanate	5 - 5.5	lab created	n/a	n/a	n/a	Normal, gentle handling
sugilite	6	dyed	to improve color	occasionally	good	Avoid solvents and ultrasonic cleaners.
sugilite	6	no treatment	n/a	n/a	n/a	Normal care
sunstone (feldspar)	6 - 6.5	not known to be treated	n/a	n/a	n/a	Avoid heat, chemicals, steam and ultrasonic cleaners.
gemstone/species (t)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
taaffeite	8	not known to be treated	n/a	n/a	n/a	Normal care
tanzanite (zoisite)	6.5	heated	to improve color	almost always	excellent	Normal, gentle handling.
tanzanite (zoisite)	6.5	coated	to improve color	sometimes	fair	Gentle wear; avoid ultrasonics and high heat.
tiger's eye, brown (quartz)	6.5	no treatment	n/a	n/a	n/a	Normal care
tiger's eye, brown (quartz)	6.5	chemical bleaching with acid or bleaching agents	to alter color	often	excellent	Normal care
tiger's eye, red (quartz)	6.5	heated	to change from gold to red	always	excellent	Normal care
	6.5	chemical bleaching with acid or bleaching agents	to alter color	sometimes	excellent	Normal care
	6.5	dyed	to alter color	sometimes	very good	Avoid sudden temperature changes, chemicals, and ultrasonic cleaners.
blue topaz (topaz)	8	irradiated and annealed	to create color	almost always	excellent	Normal care
	8	no treatment	n/a	extremely rare	n/a	Normal care
	8	CVD coated	to add color	commonly	fair to good	Color may be affected by polishing, recutting, ultrasonic cleaners, alcohol, and harsh chemicals.
brown topaz (topaz)	8	no treatment	n/a	n/a	n/a	May fade with exposure to sunlight.
brown topaz (topaz)	8	irradiated	to create color	occasionally	varies	May fade with exposure to sunlight.
green topaz (topaz)	8	irradiated	to create color	occasionally	poor	Color fades in exposure to sunlight.
green topaz (topaz)	8	CVD coated	to add color	usually	good	Color may be affected by polishing, recutting, ultrasonic cleaners, alcohol, and harsh chemicals.Color may be affected by polishing, recutting, ultrasonic cleaners, alcohol, and harsh chemicals.
topaz pink, red, mystic, ocean, glacier, patriot, canary, champagne, orchid, dawn, teal, kiwi, etc. (topaz)	8	CVD coated	to add color	commonly	fair	Color may be affected by polishing, recutting, ultrasonic cleaners, alcohol, and harsh chemicals.
topaz pink, red topaz)	8	heated	to improve color	usually	excellent	Normal care
topaz pink, red topaz)	8	irradiated	to improve color	sometimes	variable	Avoid heat and strong light.
topaz yellow, orange (topaz)	8	heated	to improve color	usually	excellent	Normal care
topaz yellow, orange (topaz)	8	irradiated	to create color	occasionally	variable	Normal care
topaz white, colorless (topaz)	8	not known to be treated	n/a	n/a	n/a	Normal care
topaz white, colorless (topaz)	8	heated	to alter color	occasionally	very good	Normal care
achroite tourmaline colorless (tourmaline)	7 - 7.5	not known to be treated	n/a	n/a	n/a	Normal care
cat's eye tourmaline (tourmaline)	7 - 7.5	no treatment	n/a	n/a	n/a	Normal care
	7 - 7.5	bleached/filled with resin	to improve clarity	rarely	fair to good	Avoid steam and ultrasonic cleaners.
chrome tourmaline	7 - 7.5	not known to be treated	n/a	n/a	n/a	Normal care
dravite brown (tourmaline)	7 - 7.5	not known to be treated	n/a	n/a	n/a	Normal care
tourmaline green,blue (tourmaline)	7 - 7.5	no treatment	n/a	n/a	n/a	Normal care
	7 - 7.5	heated	to improve color	commonly	excellent	Normal care
	7 - 7.5	oiled/resin filled	to improve appearance	occasionally	fair to good	Avoid steaming, chemicals, ultrasonic cleaners, and temperature changes.
Paraiba/cuprian tourmaline (tourmaline)	7 - 7.5	no treatment	n/a	n/a	n/a	Normal care
Paraiba/cuprian tourmaline (tourmaline)	7 - 7.5	heated	to improve color	commonly	excellent	Normal care
tourmaline pink, red (rubellite), purple (tourmaline)	7 - 7.5	no treatment	n/a	n/a	n/a	Norma care
	7 - 7.5	heated	to improve color	occasionally	excellent
	7 - 7.5	irradiated	to create color	commonly	excellent
	7 - 7.5	oiled/resin infused	to improve appearance	occasionally	fair to good	Avoid abrupt temperature changes, steaming, chemicals, and ultrasonic cleaners.
	7 - 7.5	dyed/stained	to alter color	occasionally	poor to fair
tourmaline yellow, orange (tourmaline)	7 - 7.5	heated	to improve color	rarely	excellent	Normal care
tourmaline yellow, orange (tourmaline)	7 - 7.5	irradiated	to create color	rarely	very good	Normal care
watermelon tournaline (tourmaline)	7 - 7.5	no treatment	n/a	n/a	n/a	Normal care
watermelon tournaline (tourmaline)	7 - 7.5	heated	to improve color	commonly	excellent	Normal care
tsavorite garnet (grossular garnet)	7 - 7.5	not known to be treated	n/a	n/a	n/a	Normal care
turquoise	5 -6	impregnated, waxed/oiled	to improve color and luster	commonly	poor to fair	Avoid hot water, household chemicals, and ultrasonic cleaners.
	5 - 6	dyed/stained	to improve color	often	poor
	5 - 6	stabilized	to improve durability	commonly	good
ulexite	2.5	not known to be treated	n/a	n/a	n/a	Avoid hot water, household chemicals, and ultrasonic cleaners
gemstone/species (u)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
umbalite garnet (garnet)	7 - 7.5	not known to be treated	n/a	n/a	n/a	Normal care
unakite	6 - 6.5	not known to be treated	n/a	n/a	n/a	Normal care
uvarovite garnet (garnet)	7 - 7.5	not known to be treatend	n/a	n/a	n/a	Normal, gentle handling.
gemstone/species (v)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
variscite	4.5	no treatment	n/a	n/a	n/a	Normal, gentle handling.
	4.5	impregnated with colorless plastic	to improve durability and for shaping and polishing	commonly	good	Avoid exposure to hot water, chemicals and ultrasonic cleaners.
	4.5	dyed/stained	to improve color	often	fair to good	Avoid temperature changes, steaming, chemicals, and ultrasonic cleaners.
gemstone/species (w)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
witherite	3.5	not known to be treated	n/a	n/a	n/a	Very soft and may be attacked by acids. Not suitable for jewelry.
wulfenite (specimen)	2.5 - 3	not known to be treated	n/a	n/a	n/a	Very soft, careful handling.
gemstone/species (y)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
yttrium aluminum garnet (YAG)	8.5	lab created	n/a	n/a	n/a	Normal care
gemstone/species (z)	hardness	enhancement method/s	purpose	frequency	stability/durability	care and handling
zandrite	5 - 6	man-made	n/a	n/a	n/a	Normal, gentle handling
blue zircon (zircon)	7 - 7.5	heated	to create color	almost always	fair to good	Normal, gentle handling and avoid ultraviolet light.
colorless zircon (zircon)	7 - 7.5	heated	to lighten color	almost always	fair to good	Normal, gentle handling and avoid ultraviolet light.
zircon green, brown (zircon)	7 - 7.5	not known to be treated	n/a	n/a	n/a	Avoid harsh abrasives.
hyacinth pink zircon (zircon)	7 - 7.5	heated	to produce color	commonly	fair to good	Avoid harsh abrasives and strong light.
red zircon (zircon)	6.5 - 7.5	heated	to improve color	rarely	good	Avoid harsh abrasives and strong light.
yellow zircon (zircon)	6.5 - 7.5	heated	to improve color	rarely	good	Avoid harsh abrasives.

gem enhancement codes (based on AGTA guidelines)
assembled	The assembling of natural with natural and/or man-made parts to improve durability or appearance. Examples: opal doublet, mabe pearl.	AS
bleached	The use of heat, light, and/or chemicals or other agents to lighten or remove a gemstone's color. This is sometimes accompanied by subsequent dying and/or impregnating to stabilize the resulting color. Examples: cultured pearl, golden coral, B-jade	BL
coated	The use of such surface enhancements as lacquering, enameling, inking, foiling, or sputtering of films to improve appearance, improve durability,provide color or add other special effects. Examples: some pearls, black star sapphires, some topaz.	CTD
CVD coated	"Chemical Vapor Deposition" - A high-tech coating that is commonly applied to the pavillion (bottom) of stones to change or improve their color. Examples: diamond, mystic topaz.	CVD
channel/pipe diffusion*	The high temperature diffusion of coloring elements, such as copper, along certain channels in feldspars. Example: andesine-labradorite. *Research still in progress	DIF
dyed/stained	The introduction of coloring matter into a gemstone to give it new color, intensify existing color or improve color uniformity. Examples: dyed green jadeite, lapis.	DYED
fracture filled	The filling of surface-breaking cavities or fissures with colorless glass, plastic, resin or some similar substance. This process may improve appearance, durability and/or weight. Examples: ruby, emerald.	FF
lead glass filling	A similar process to "fracture filled" using lead glass. Performed at lower temperatures, this is a less durable treatment and should be treated gently. Examples: plum star ruby, some ruby.	FF
flux healed	During heat enhancement, fluxes (or heat alone) may be used to heal fractures/fissures which were formerly open. The process dissolves the walls of the fractures and redeposits the molten gem material, healing the fractures closed. Example: ruby.	FH
heated	The use of heat to alter color, clarity, and/or phenomena. Examples: ruby, sapphire, tanzanite, aquamarine, demantoid garnet.	HE
HTHP	The use of high heat and pressure combined to affect desired alterations of color and/or clarity. Example: colored and near-colorless diamonds.	HPHT
impregnated	The impregnation of a porous gemstone with a colorless agent (usually plastic) to give it greater durability and improve appearance. Examples: stabilized turquoise, coral.	IMP
irradiated	The use of neutron, gamma, ultraviolet and/or electron bombardment to alter a gemstone's color. The irradiation may be followed by a heating/annealing process. Examples: blue topaz, colored diamonds.	IRR
lasered	The use of a laser and chemicals to reach and alter inclusions. Example: diamond.	LAS
surface diffusion	The outside-in diffusion of elements via high-temperature heat treatment to produce a layer of color and/or asterism. Examples: some blue sapphire, some star sapphire.	DIF
lattice diffusion	The heat treatment at high temperatures with elements that deeply penetrate the gem material to alter the color. Examples: padparadscha sapphire, yellow sapphire.	DIF
normally enhanced "E"	The "E" symbol is used for gemstones that are routinely enhanced. Since many enhancements are difficult or impractical to prove definitively, unless otherwise indicated, our approach is to assume that such enhancements have been applied to that particular gemstone. This assumption is made to protect both buyer and seller. If a more specific method of enhancement is known, then the specific enhancement code will be used.	E
not known to be treated "N"	The "N" symbol is used on our invoices to indicate one of two situations: First, there are certain gemstones that are not currently known to be enhanced (such as alexandrite and most garnets). Secondly, the "N" symbol may also be used for a gem where it can be proved via gemological or other means that a gem has not been subjected to any enhancement. When you see the "N" symbol on our invoice, Jewelry Television guarantees that your gem is unenhanced.	N
oiled/resin infused	The filling of surface-breaking fissures with a colorless oil, wax, resin, or other colorless substance except glass or plastic, to improve the gemstone's appearance. Example: emerald.	O=OIL R=RESIN
stabilized	Not to be confused with reconstituted turquoise, the more valuable stabilized turquoise is solid, whole turquoise that has been filled with colorless wax or resin to fill tiny gaps within it, providing a polished finish that protects the stone against breakage and discoloration resulting from exposure to skin oils, etc. Stabilization is not a color enhancement. Stabilization only serves to protect the turquoise and help it retain its original, natural color.	STAB
waxed/oiled	The impregnation of a colorless wax, paraffin, and/or oil in porous gemstones to improve their appearance. Example: coral, amazonite.	W=WAXED O=OIL
*research in progress	Possible enhancement methods and any special care recommendations required for gems marked with an asterisk (*) are currently being researched/revised due to new developments and/or the rarity of this stone in the jewelry trade. When in doubt, the safest way to care for gemstones and jewelry with unknown enhancements is cleaning with a soft brush and warm water with the addition of a mild detergent when necessary, avoiding extreme temperatures, and avoiding prolonged exposure to bright light. Our sources include, but are not limited to, university mineralogical, gemological, and geology departments, as well as international gem laboratories and individual experts in the trade. This page will be regularly updated as information becomes available.
stability	Stability is the ability to resist deterioration.
durability	Durability is the ability to withstand scrathing.
color enhanced	Stones have been enhanced by a coloring agent
clarity enhanced	Stones have been enhanced with colorless glass, oil, plastic, resin or some similar substance
treated	Stones that have been treated by irradiation, diffusion, coatings, lasering, etc.
synthetic	a lab-grown gemstone that matches the chemical and physical properties of a natural material
simulant or imitation	a material - natural, synthetic or artificial - that imitates a natural product
artificial	any man-made material
lab created Synthetic/Simulant	There are various types of lab created gems. Synthetic gems are identical to their natural counterparts in chemistry and composition, but are grown in an artificial environment. Example: Synthetic alexandrite, Synthetic emerald. Simulants are also grown in an artificial environment and are often crystalline materials, but will not have the chemical or physical properties of the gem they resemble. Example: Synthetic sapphire that looks like tanzanite, Orange CZ that looks like Mandarin Garnet. Imitations may be natural or lab created materials that resemble or are treated to resemble other materials. Example: jasper dyed to look like lapis, quartzite dyed to look like turquoise, quench-cracked/dyed quartz to look like emerald

JTV HAS A RIGOROUS PROTOCOL TO VERIFY THE TREATMENT OF ALL GEMSTONES WE SELL. OUR TREATMENT DISCLOSURES ABOVE, ON AIR, AND ON OUR INVOICES INCLUDE THE INFORMATION WE KNOW ABOUT A GEMSTONE. IT IS POSSIBLE THAT A GEMSTONE HAS BEEN TREATED OR ALTERED WITHOUT OUR KNOWLEDGE OR THAT THE METHOD OF TREATMENT IS NOT KNOWN TO US OR DETECTIBLE BY CURRENT ACCREDITED LABORATORY TESTING TECHNOLOGY. THEREFORE, THE TREATMENT INFORMATION PROVIDED ABOVE, ON AIR, AND ON OUR INVOICES IS TO THE BEST OF OUR KNOWLEDGE.

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