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Jewelry Books

Diamond Ring Buying Guide by Renee Newman
Consumer-oriented book filled with useful information, drawings & pictures for 1st time diamond buyer.

Photo Masters of Diamond Grading by Gary Roskin
Photo Masters is a compilation of 244 extraordinary photomicrographs, suitable for students or experienced diamond graders.

Blood Diamonds

Blood Diamonds cost torture & death for Sierra Leone residents. Conflict Diamonds finance civil wars & terrorists, including al Qaeda.

Antique Price Guide

By Judith Miller, author of more than 80 books on antiques, including "How to Make Money Out of Antiques."



Round Brilliant Cut


Rounds are the most popular Shape that Diamonds are cut into. It is also the most brilliant of all the cuts. You may have heard of a term called "Ideal Cut". This term refers to the attempt to cut a Diamond into the best proportions to achieve maximum brilliance. The following is a breakdown of what is considered "Ideal Cut" in round brilliants according to "American Ideal / Tolkowsky" and the "European Ideal Cut" (Proportions are given relative to the girdle diameter):


"Ideal Cut" for Rounds
  American Ideal /
European Ideal
Total Depth 58.7 - 62.3% 60.0 - 61.1%
Table Diameter 53.0 - 58.0% 57.5%
Girdle Thickness medium
slightly thick
very thin
Culet Size none
Crown Angles 34.3 to 34.7 34.5
Pavilion Depth 43.1% 43.1%
Finish very good
Crown Height 16.2% 16.2%


Be aware that there is a premium for purchasing "Ideal Cuts", and they are more rare in the market. Cutting to "Ideal" generally entails losing more weight from the rough Diamond than regular proportions.

cutillustrate.gif (4224 bytes)

There are 58 facets in a Round Brilliant Cut including the culet. On the Crown or upper part of the Diamond, these consist of 1 table facet, 8 bezel facets, 8 star facets, and 16 upper girdle facets for a total of 33. On the pavilion, or bottom part of the Diamond, there are 16 lower girdle facets, 8 pavilion main facets and 1 culet.

Rounds are the most expensive cuts, and with good reason. It is usually possible to retain more weight from a Rough (unpolished) Diamond if it is cut into a Fancy shape than if it is cut to a Round.


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