Diamond Color Grading Tips
Color Grading Tips - You should keep following things in mind while
doing color grading of white diamond in order to achieve best results.
- Diamond should be graded in loose form, as when mounted on metal, metal color can influence the actual color of stone.
- Diamond and master-stones (set of master diamonds provided by GIA for color comparison) should be clean.
- Atmosphere and surrounding should not be too bright to influence the original color of diamond.
- White light should be used and it should be so adjusted that it
falls directly on the stone and not on eyes. In case of dark room, light
equivalent to day light should be used.
- Diamond should be viewed with 10X loupe and diamond should be
positioned "table- down" and "pavilion-up" i.e. upside down and look
|Diamond Grading Loupe
- Broadest part of the pavilion just above from the girdle (as we are
studying diamond upside down) should be studied. Master stones should be
placed in identical position of the stone being studied.
- Generally, two diamonds (to be graded) should not be compared with
each other. If necessary keep 1 cm distance between them. In any
condition, two diamonds should not be touching each other.
- Some diamonds fluoresce, so while doing color grading, do check Presence of fluorescence in white diamond by exposing diamond to ultra-violet light and grade diamond accordingly.
I hope above provided color grading tips will help you during color grading of white diamonds.
Use of Shade card while Color Grading
When in case of doubt about color shade of diamond, use Shade Card
for reference. It is basically, folded white paper used to color grade
diamonds. The folded paper is held between thumb and finger tips at
distance of 10 cm from light.
|Diamond Color Shade Card
Stones are placed upside down on channel
of fold (horizontal plane of paper). The stone is studied perpendicular
to the pavilion facets about halfway up the pavilion towards the culet.
While grading slightly move the shade
card, alter the position of light falling on diamond. Move the shade
card closer to light or move slightly away to best judge the color of
Points to be considered while using Shade Card
- Shade card should be white and clean. Diamond to be graded should be clean. If dusty, stone should be cleaned from a soft cloth.
- When two diamonds are compared then those should be kept at least 1 cm apart. Otherwise their color influences each other.
- Color defects in diamond (black spots, Newton ring or red spots)
should be twisted and viewed from back and not from the front of
diamond, i.e. not through table of diamond. This is because color
defects could influence the original color of diamond.
- If the diamond is too shiny it should be breathed on, i.e. when
vapor is passed on diamond, it becomes dull and it could be judged
correctly when vapor begins to clear out from diamond surface.
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