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Any traditional process other than
cutting and polishing that improves the appearance (color/ clarity/phenomena),
durability or availability of a gemstone is considered enhancement. Most popular
gemstones are undergone some kind of treatments, and all permanent techniques
are universally accepted. For instance, most ruby or sapphire you'll find has
been heated to enhance the gemstone to amazing colors of blue and red.
While these treatments are
taken as commonplace within the industry, the general public's awareness has
been much lower. Further information of treatment codes can be found by
clicking here or
or alternatively access the guidelines provided by the
U.S. Federal Trade Commission.
The following table provides information on the
treatments and care used for specific types, their purpose and frequency:
| Gemstone |
Tag Code |
Treatment/
Frequency |
Stability |
Care Tips |
|
Alexandrite |
N |
None |
-- |
Normal |
|
Amazonite |
I, W or
E |
Usually
- colorless wax, oil, harden resin |
Good -
fair |
Avoid
heat, chemical, ultrasonic |
|
Amber |
E or H,
D |
Usually
- heated, dyed |
Very
good - good |
Avoid,
chemicals, ultrasonic |
|
Amethyst |
E or H |
Sometimes - heated |
Excellent |
Unheated
stone may fade in long sunlight's exposure |
|
Ametrine |
N |
None |
-- |
Normal |
|
Aquamarine |
E or H |
Usually
- heated |
Excellent |
Normal |
|
Chalcedony |
|
Agate |
D or H |
Usually
- dyed |
Excellent |
Avoid
strong heat, acids |
|
Black Onyx |
D |
Always -
dyed |
Excellent - good |
Avoid
strong heat, acids |
|
Carnelian |
E or H,
D |
Usually
- heated, dyed |
Good -
fair |
Avoid
strong heat, acids |
|
Jasper |
D |
Sometimes - dyed |
Excellent - good |
Avoid
strong heat, acids |
|
Chrysoprase |
N |
None |
-- |
Avoid
strong heat, acids |
|
Chrysoberyl |
|
Cat's Eye |
R |
Sometimes - Irradiated |
Excellent |
|
|
Alexandrite (Yellow, Brown, Green) |
N |
None |
-- |
Normal |
|
Coral |
|
Black |
N |
None |
-- |
Avoid,
chemicals, cosmetics, ultrasonic |
|
White |
E or B |
Commonly
- bleached |
Good |
Avoid,
chemicals, cosmetics, ultrasonic |
|
Pink |
E or W |
Commonly
- colorless waxed |
Good |
Avoid,
chemicals, cosmetics, ultrasonic |
|
Gold |
B |
Sometimes - bleached |
Very
good |
Avoid,
chemicals, cosmetics, ultrasonic |
|
Red |
D |
Sometimes - dyed |
Variable |
Avoid,
chemicals, cosmetics, ultrasonic, fade in light or heat |
|
Emerald |
E or O,
D |
Usually - resin/oil infusion,
Occasionally - Dyed |
Very
good - fair |
Avoid
thermal shock, steaming |
|
Garnet |
|
Almandite |
N |
None |
-- |
Avoid
thermal shock |
|
Demantoid |
N |
None |
-- |
Avoid
thermal shock |
|
Pyrope |
N |
None |
-- |
Avoid
thermal shock |
|
Rhodolite |
N |
None |
-- |
Avoid
thermal shock |
|
Tsavorite |
N |
None |
-- |
Avoid
thermal shock |
|
Hematite |
N |
None |
-- |
Normal |
|
Iolite |
N |
None |
-- |
Normal |
|
Jade |
|
Jadeite |
E or W,
B |
Usually - waxed,
Commonly - bleached |
Fair
Poor |
Avoid
ultrasonic, chemicals, heat |
|
Green, white & purple |
B, S, D |
Commonly - bleached,
Sometimes - dyed, polymer
impregnation |
Very
good
Variable |
Avoid
ultrasonic, chemicals, heat |
|
Lapis Lazuli |
E or W,
D |
Commonly
- dyed, colorless wax or oil |
Fair |
Avoid
ultrasonic, chemicals, heat |
|
Malachite |
W, I |
Sometimes - colorless wax,
Rarely - plastic impregnation |
Fair
Good |
Avoid
ultrasonic, chemicals, heat |
|
Moonstone |
N |
None |
-- |
Normal |
|
Opal |
|
white & black |
O, I |
Rarely -
oil & was impregnated, resins infusion |
Good -
fair |
Avoid
ultrasonic, solvents, heat |
|
Boulder |
O |
Sometimes - oil impregnated |
Fair |
Avoid
ultrasonic, solvents, heat |
|
Fire Opal |
O, I |
Usually - resins infullion, oil impregnated |
Good -
fair |
Avoid
ultrasonic, solvents, heat |
|
Pearl |
|
Natural |
E or B,
D |
Usually - bleached,
Rarely - dyed |
Excellent |
Avoid
cosmetics, chemicals |
|
Cultured |
E or B,
D |
Usually
- bleached, dyed |
Very
good |
Avoid
cosmetics, chemicals |
|
Peridot |
E or O,
F |
Rarely -
oil waxed, filling |
Good |
Avoid
thermal shock, chemicals, ultrasonic |
|
Quartz |
|
Aventurine |
E or H |
sometimes - heated |
Excellent |
Unheated
stone may fade in long sunlight's exposure |
|
Citrine |
E or H |
sometimes - heated |
Excellent |
Unheated
stone may fade in long sunlight's exposure |
|
Rock Crystal |
E or H |
sometimes - heated |
Excellent |
Unheated
stone may fade in long sunlight's exposure |
|
Rose Quartz |
R |
sometimes - irradiated |
Very
good |
May fade
in long sunlight's exposure |
|
Smoky Quartz |
R |
sometimes - irradiated |
Very
good |
May fade
in long sunlight's exposure |
|
Tiger's eye |
E or H |
sometimes - heated |
Excellent |
Unheated
stone may fade in long sunlight's exposure |
|
Rhodonite |
D |
Sometimes - dyed |
Poor |
Avoid
chemicals, ultrasonic |
|
Ruby |
H, D, F,
R, U |
Usually - heated,
Rarely - dyed, filling,
irradiated, diffused |
Excellent Good - fair |
Avoid
chemicals, ultrasonic, pressure, repolishing, recutting |
|
Sapphire |
H, U, R |
Usually - heated,
Rarely - irradiated, diffused |
Excellent Good - poor |
Avoid
repolishing, recutting, fades in light or heat |
|
Spinel |
N |
None |
-- |
Normal |
|
Tanzanite |
E or H |
Usually
- heated |
Excellent |
Avoid
thermal shock |
|
Topaz |
|
Blue |
R |
Usually
- irradiated |
Excellent |
Avoid
ultrasonic, thermal shock |
|
Yellow/ Orange |
R |
Usually
- irradiated |
Variable |
Avoid
ultrasonic, thermal shock |
|
Tourmaline |
|
Green, Blue |
E or H |
Commonly
- heated |
Excellent |
Avoid
ultrasonic, chemicals, thermal shock |
|
Pink, Red |
H, R |
Sometimes - heated,
Commonly - irradiated |
Excellent
Good - fair |
Avoid
ultrasonic, chemicals, thermal shock |
|
Yellow/ Orange |
H, R |
Sometimes - heated,
Commonly - irradiated |
Excellent
Good - fair |
Avoid
ultrasonic, chemicals, thermal shock |
|
Bicolored |
E or H |
Commonly
- heated |
Excellent |
Avoid
ultrasonic, chemicals, thermal shock |
|
Turquoise |
I, W, D |
Commonly - plastic & oil impregnated,
Rareli - dyed |
Good -
fair
Poor |
Avoid
hot water, chemicals |
|
Zircon |
|
Blue |
E or H |
Routinely - heated |
Good -
fair |
Avoid
harsh abrasives |
|
Green |
E or H |
Routinely - heated |
Good -
fair |
Avoid
harsh abrasives |
|
Yellow |
E or H |
Sometimes - heated |
Good -
fair |
Avoid
harsh abrasives |
|
Colorless |
E or H |
Routinely - heated |
Good -
fair |
Avoid
harsh abrasives |

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