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Products & Services> Loose Colored Stones
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Gem & Mineral Catalog
IndyGem is
pleased to offer the many gemstone listings which are featured down the
left hand column on all of our pages. These listings contain calibrated
sizes and shapes, in various qualities, of the most popular gemstones
which our customers seek. Our listings also contain many rare and
unusual varieties which we are pleased to offer to those seeking fine,
one of a kind collection quality stones. The "Collection"
series headings will be obvious on many of these latter categories.
These listings are to be used in the completion of custom designs, or
just for collectors.
Most of these tables will have a column headed by AGTA, which stands for
American Gem Trade Association. In
most cases,
if the column is omitted, it is because the stone is not normally
treated or enhanced (category N
below). However, we recommend that with any gemstone, it is safer to
assume that it has been treated or enhanced, unless it can be proven
otherwise. We will make every attempt to verify for you the status of
any of the gemstones which we sell.
The AGTA has designed a coding system which assists in the proper
disclosure of treatments and enhancements which many colored gemstones
routinely encounter. The following information will explain the various
codes used. Please feel free to contact us at any time for explanations
or clarification on any of these as they may affect any colored stones
which you may be interested in. Also IndyGem frequently assists in the
locating and acquisition of specific stones which may not appear on our
lists.
We apologize if any of the stones listed are no longer available at the
time of your inquiry. While we make every attempt to maintain our lists
regularly, many of the "Collection" Series stones are
extremely rare and available only as located. On the occasion that a
listed stone is unavailable, we will make every effort to locate a comparable
stone within a reasonable time.
Gemstone
Enhancements
The following codes and definitions are adapted from the American Gem
Trade Association's Gemstone Enhancement Manual, Edition 6.1 June, 1997,
which is the industry standard for disclosure to consumers.
General Enhancement
Categories:
1) N:
Those natural stones which are not currently known to be enhanced by any
methods, such as spinel, and therefore can safely be presumed untreated.
The symbol "N" is used for these and may also be used in the
case of other stones which are sometimes or often treated, which in the
particular case are unenhanced. To use this symbol on sapphire, for
example, which is generally heated means that the seller certifies that
the particular stone was not heated and supplies a document such as an
invoice or lab report so stating.
2) E:
Those natural stones which are routinely enhanced by traditional
methods, the particular stone given this designation, may or may not be
enhanced. For example, since most emeralds are oiled an E would indicate
such treatment, but would not cover non-traditional methods such as
hardened plastic resins (like Opticon) which would require specific
enhancement codes such as those listed below. Another example would be
the use of E for aquamarine, which in most cases is heated prior to the
sale of the rough to remove greenish tints. If the seller knows what
specific treatment has been used, then a more specific code should be
used.
3) Those gemstones for which definite information on standard treatments
is known, or to which N and E codes do not apply, as they have been
treated in non-traditional ways which must be specifically disclosed by
the appropriate code and also in writing. For example, a ruby which has
had fractures or cavities filled with glass would receive an I
(infilling) code as described below. A Morganite, which is known to have
been heated, would receive an H
rather than the less specific, E.
Specific
Enhancement Codes:
B: Bleaching
- Use of chemicals to lighten or remove a gem's color
C: Coating
- Use of surface treatments such as films, lacquers, etc. to provide
color or other special effects
D: Dyeing
- The introduction of coloring matter into a gem to give it a new color
or greater intensity
F: Filling
- Incorporation of colorless borax or other substances into cracks as a
by-product of heating the stone, used only if such material is visible
at 10x.
G: Gamma/Electron
Radiation - The use
of gamma or electron irradiation for the purpose of changing a gem's
color, may be followed by a heating process to stabilize the color. Such
stones do not exhibit residual radioactivity.
H: Heating
- The use of heat to clarify, change color or create phenomena in gems.
Any filler materials, which enter the gem, as a result must not be
visible in fractures at 10x.
I: Infilling
- The intentional filling of surface breaking cracks and cavities with a
foreign material such as synthetic resins with hardeners (Opticon),
glass or plastic.
L: Lasering
- The use of a laser to drill into a stone and remove or alter an
inclusion, refers specifically to diamonds
O: Oiling or Resin
Infusion - The
intentional filling of surface breaking cavities and cracks in
transparent or translucent gems with a colorless oil, wax, resin or
man-made unhardened resin.
R: Irradiation
- The use of neutron bombardment to alter color. This process creates
residual radioactivity and such stones must receive a Nuclear Regulatory
Commission safety release prior to sale. Usually used in combination
with other radiation and or heating treatments.
S: Bonding
- The intentional use of a colorless bonding agent (usually plastic)
within a porous gemstone.
D: Diffusion
- The use of specific chemicals during a high temperature heating
process for the purpose of penetrating the surface layer (usually to a
slight depth only) with coloring or star-making chemicals. Such
treatment is not generally accepted and stones sold with this
enhancement must be specifically labeled as diffused.
W: Waxing/Oiling
- The impregnation of colorless wax, oil or paraffin into porous opaque
gems to improve appearance.
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