I've listed a selection of a few websites with good information about the 4c's, and also websites which give an explanation of how to read a certificate and what to look for. It's almost like a mini-on-line-diamond-course.|
|Explanation of the 4c's|
This website's "Diamond Dictionary" explains certificate terminology: facets, culet, depth, fluorescence, length-to-width ratio, polish, symmetry, and the table. "The Whole Story" describes the progression of a stone from the mine through the polishing stages.
|Explanation of the Certificate|
- www.diamondsource.com This website's topic "How to Read a Diamond Certificate" covers clarity grade, shape and cut, measurements, weight, proportions, depth, table, girdle, culet, polish, symmetry, color grades, fluorescence, diagram, and comments. Questions can
be e-mailed to: email@example.com
This website gives an interesting explanation of the the limitations of a diamond certificate, and asks "if the whole story is working" when it comes to a diamond. Also information about color and clarity influences on the diamond.
Gemological Laboratories - Worldwide|
- AGS www.ags.org
- EGL European Gemological Laboratory CLICK to access their site, www.egl.co.za EGL is an interational network with gemological laboratories in
Ramat Gan, Antwerp, London, Los Angeles, New York, Paris, Seoul.
The lab offers certificates, mini-certs, and laser inscription on request; and grades for SI3 and has specialized specifications for Ideal, Excellent, Tolkowsy, and Premium cuts.
- GGL www.globalgemlab.com
- HRD www.diamonds.be
- IDI www.diamonds.org.il
- GIA www.gia.org Carlsbad and Los Angeles, California; Kowloon, Hong Kong; Vicenza, Italy;
Tokyo, Japan; Seoul, Korea; Moscow, Russia; Taipei, Taiwan; Bangkok, Thailand
- GQI Gem Quality Institute www.gqi.com
- Harold Weinstein Ltd. Gemology Lab www.hwgem.com
- Precious Stone Lab www.precious-stonelab.co.uk
- South Africa Diamond Certified Lab - Jewelry Council
- Indian Diamond Institute Surat Tel:(91 26) 1 480809 Fax:(91 26) 1 481110
- United States Gem Lab www.usgl.com
- Zenhokyo Ltd. Tel:(972-3) 575-6036
Schools and Correspondence
- EGC European Gemological College
- EGL European Gemological Laboratory www.egl.co.za
- Zenhokyo Ltd. Gemological Association
of All Japan, Inc. Network Tokyo Tel: (03)3835-7484
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Revised: 14 May 01 1800 GMT