Gemstone Enhancements
The term enhancement is defined as any treatment or process other than
cutting and polishing that improves the appearance
(color/clarity/phenomena), durability, value
or availability of a gemstone. In today’s
gem marketplace, many gemstones have been enhanced
by a variety of methods. Such processes may
range from simple heating (such as with tanzanite)
to high-tech irradiation (such as blue topaz).
At
Pala International, we take enhancement disclosure
seriously and guarantee, to the best of our
abilities, to provide our customers with
complete information on any and all enhancements
to which a gem has been subjected. While
many enhancements are currently undetectable,
we do our best to provide all the information
you need for informed buying decisions.
The
guidelines we follow are those of the AGTA and
are the most stringent in the industry. In
addition, we have modified these guidelines
slightly in areas where we feel they are
not stringent enough (example: flux healing
of ruby).
Some
gemstone enhancements are less stable than
others, meaning that the appearance of a
gem may change with time. It is the general
policy of Pala International to sell only
those gemstones whose enhancements (if any)
have good to excellent stability.
In the event that we offer a gem with less
than good stability, we will ensure you are
aware of the special care needed for that
stone. A gemstone enhancement is considered
stable as long as the gem does not change
in appearance (color and/or clarity) under
normal wear, cutting, cleaning, repair or
display conditions. Gemstones can be divided
into three basic enhancement categories.
Symbols for Specific Forms of Enhancement
Natural Gemstone Enhancement Chart
(based on the AGTA Source
Directory 20002001)
Natural Gemstone |
Enhancement Symbol |
Description Used |
Frequency Encountered |
Stability | Care Requirements |
Agate | D | | Usually | Excellent to good | Normal |
Fire Agate |
N | | | | Normal |
Alexandrite | N | | | | Normal |
Amber | E or H | | Usually | Very good to good | *Special |
D | | Rarely | Variable | Special | |
Amethyst | E or H | | Occasionally | Excellent | *Special |
Ametrine | N | | | | Normal |
Andalusite | N | | | | Normal |
Aquamarine | E or H | | Usually | Excellent | Normal |
Beryl | R | Maxixe | Always | Poor | X-Special |
R | Yellow | Usually | Variable | Special | |
N | Yellow-green | | | Normal | |
E or O | Red | Commonly | Very good to fair | Special | |
Chalcedony | D | Black | Always | Excellent to good | Normal |
D | Banded | Usually | Excellent | Normal | |
D | Green | Usually | Good to fair | Special | |
D | Blue | Commonly | Good to fair | Special | |
E or H | Carnelian | Usually | Excellent | Normal | |
D | Carnelian | Occasionally | Excellent to good | *Special | |
D | Jasper | Occasionally | Excellent | Normal | |
N | Chrysoprase | | | Normal | |
Chrysoberyl | N | Transparent | | | Normal |
R | Cat’s eye | Occasionally | Excellent | Normal | |
Citrine | E or H | | Usually | Excellent | Normal |
Coral | N | Black | | | *Special |
E or B | White | Commonly | Good | Special | |
E or W | Pink | Commonly | Good | Special | |
I | Orange | Commonly | Good | Special | |
B | Gold | Usually | Very good | Special | |
D | Red | Occasionally | Variable | X-Special | |
Natural Gemstone |
Enhancement Symbol |
Description Used |
Frequency Encountered |
Stability | Care Requirements |
Diamond | L | | Occasionally | Very good | Normal |
C | | Rarely | Very good to poor | Special | |
F | | Occasionally | Very good | Special | |
HP | | Rarely | Unknown | Special | |
Diamond Fancy | R | | Occasionally | Excellent to very good | Special |
L | | Occasionally | Very good | Normal | |
F | | Rarely | Very good | Special | |
C | | Rarely | Fair to poor | Normal | |
H | | Rarely | Unknown | Normal | |
Diopside Chrome | N | | | | *Special |
Emerald | E or O | | Usually | Very good to fair | Special |
D | | Occasionally | Variable | Special | |
Garnet | N | All varieties | | | *Special |
E or H | Some demantoid | Commonly | Very good | *Special | |
Hematite | N | | | | Normal |
Iolite | N | | | | Normal |
Jade Jadeite | E or W | | Commonly | Fair | Special |
B and I | Green/purple/white | Commonly | Very good to good | Special | |
D | | Occasionally | Variable | Special | |
B and W | | Rarely | Poor | Special | |
Jade Nephrite | D | | Rarely | Unknown | Special |
Kunzite | E or H | | Commonly | Fair | Special |
R | | Commonly | Fair | Special | |
Natural Gemstone |
Enhancement Symbol |
Description Used |
Frequency Encountered |
Stability | Care Requirements |
Lapis lazuli | E or W | | Commonly | Fair | Special |
D | | Commonly | Variable | Special | |
Moonstone | N | | | | Normal |
Morganite | E or H | | Commonly | Excellent | Normal |
Opal | O | White/black | Rarely | Fair | Special |
I | | Rarely | Good | Special | |
O | Boulder | Usually | Good | Special | |
D | Matrix | Commonly | Good | Special | |
N | Fire opal | | | *Special | |
I | Cat’s eye | Usually | Good | Special | |
I/O/D | Hydrophane | Commonly | Good to fair | Special | |
Pearl Natural | E or B | White | Usually | Very good | Special |
D | | Rarely | Very good to good | Special | |
Pearl Cultured | E or B | White | Usually | Excellent | Special |
D | Many colors | Usually | Variable | Special | |
R | Black/gray | Occasionally | Very good | Special | |
Peridot | E or O | | Rarely | Good to fair | Special |
F | | Rarely | Good | Special | |
Ruby | E or H | | Usually | Excellent | Normal |
Fh | | Commonly | Excellent | Normal | |
O | | Occasionally | Good to fair | Special | |
D | | Rarely | Poor | Special | |
R | | Rarely | Unknown | Normal | |
F | | Commonly | Very good to fair | Special | |
U | | Rarely | Good | Special | |
Natural Gemstone |
Enhancement Symbol |
Description Used |
Frequency Encountered |
Stability | Care Requirements |
Sapphire | E or H | | Usually | Excellent | Normal |
U | | Occasionally | Good to fair | Special | |
O | | Occasionally | Good to fair | Special | |
Sapphire Fancy | E or H | | Usually | Excellent | Normal |
R | Yellow/orange | Occasionally | Very poor | X-Special | |
O | | Occasionally | Good to fair | Special | |
U | | Occasionally | Good to fair | Special | |
Serpentine | D | Various colors | Commonly | Good to fair | Special |
E or W | | Commonly | Very good to good | Special | |
Spinel | N | | | | Normal |
O | | Occasionally | Good to fair | Special | |
Sugelite | N | | | | Normal |
Sunstone | N | | | | Normal |
Tanzanite | E or H | | Usually | Excellent | *Special |
Topaz | R | Blue | Usually | Excellent | Normal |
R | Yellow/orange | Occasionally | Variable | Special | |
R | Green | Occasionally | Poor | X-Special | |
U | Green | Usually | Good | Special | |
N | Brown | | | *Special | |
E or H | Red/pink | Usually | Excellent | Normal | |
Natural Gemstone |
Enhancement Symbol |
Description Used |
Frequency Encountered |
Stability | Care Requirements |
Tourmaline | N | Chrome green | | | Normal |
N | Cat’s Eye | | | Normal | |
E or H | Yellow/orange | Rarely | Excellent | Normal | |
R | Yellow/orange | Rarely | Very good | Normal | |
E or H | Green/blue | Commonly | Excellent | Normal | |
O | Any color | Occasionally | Good to fair | Special | |
E or H | Pink/red/purple | Occasionally | Excellent | Normal | |
R | Pink/red/purple | Commonly | Good | Normal | |
D | Pink/red/purple | Occasionally | Fair to poor | Special | |
Turquoise | W | | Commonly | Fair to poor | Special |
D | | Rarely | Poor | X-Special | |
I | | Commonly | Good | Special | |
Zircon | N | Green/brown | | | *Special |
E or H | Blue/colorless | Always | Fair to poor | Special | |
E or H | Yellow | Rarely | Good | Special | |
E or H | Red | Commonly | Fair to poor | Special |
Notes:
If you need additional information on gemstone enhancements or care, call us at: 800-854-1598.