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COLOR:
Considered the most important. Each gemstone has its own
specific colors, and each has its most desired color which will
vary from one geographic area to another. Generally the richer
(darker, but not too dark) and brighter the color and the more
even color distribution, the prettier and more expensive the
gemstone will be. The duller, more zoned and lighter colored
gemstone will usually be more reasonable. Color grade can be 70%
of the total value of the gemstone.
Hue:
The essential impression of color that we notice immediately
(Red, Blue, Greenish Yellow, etc)
Tone:
The color's lightness or darkness. (Light, Medium, Dark)
Saturation:
Purity of the color. The more grayish or brownish, the lower the
saturation and the duller the color. Gemstones that have real
dark tone, or real light one (washed out) never reach a high
saturation. The desired appearance is appealing and bright and
could be called "Vivid".
Vivid-Bright (6) 5
Medium (4-3) 2 Dull Brown-Gray (1)
CUT:
(Quality/Polish/Finish) - Excellent (10 - 8) Very Good (7 - 6)
Good (5 - 4) Fair (3 - 1)
CLARITY:
The degree of freedom from visible characteristics put there by
Mother Nature during the stone's growth. Clarity grades for
colored gemstones are categorized into three areas: Type I that
are generally very clean and are penalized more than Type II for
having any inclusions and Type III, where inclusions are
expected and not penalized as heavily as Types I & II.
Type I
Aquamarine, Chrysoberyl, Citrine, Topaz, Smoky Quartz, Green
Tourmaline, Tanzanite and Blue Zircon.
Type II
Alexandrite, Amethyst, Garnets, Peridot, Iolite, Ruby, Sapphire,
Spinel, all Tourmaline except red and green.
Type III
Emeralds, Red & Pink Tourmalines.
VVSI - Very, Very Slightly
Included (the best) Minute inclusions that are difficult to see
using 10X, and are not visible at all to the naked eye.
VSI - Very Slightly Included
Minor inclusions that are easier to see using 10X, but still not
visible to the naked eye.
SI1 - Slightly Included I
The inclusions are easily seen using 10X, and are noticeable
with the naked eye.
SI2 - Slightly Included 2
The inclusions are more easily seen using 10X, and are quite
visible with the naked eye.
I1 - Included 1 The
inclusions are very obvious and they have a moderate negative
effect on the over-all appearance or durability of the gemstone.
I2 - Included 2 The
inclusions are very obvious and they have a severe negative
effect on the over-all appearance or durability of the gemstone.
I3 - Included 3 The
inclusions are very obvious and they have a severe negative
effect on both the over-all appearance and durability of the
gemstone.
Declasse - stones not
transparent because of inclusions
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