By Charles I Carmona
Gemania Publishing Company
1998 ISBN 0-9666370-0-3
Richard Liddicoat writes:
A serious problem for all of those who are called upon to appraise or identify the gems set in various types of jewelry is first to ascertain not only the identity of the gems, but also the weight of the gems in rings, bracelets, necklaces—or other forms. Often, the nature of the mounting makes it difficult.
Charles Carmona has spent many years assembling and / or developing a remarkably comprehensive set of weight estimation formulae for mounted diamonds, colored stones and pearls—and used them to prepare detailed tables based on millimeter measurements. Those who appraise, buy, sell, insure or loan on used or estate jewelry depend on accuracy in weight estimation. Such individuals engaged in activities involving a need for accuracy in weight estimations for estate purposes, appraising, identification, pawnbroking of jewelry, or other needs should consider such detailed tables a major resource in their estimating process. Obviously most practitioners have some means of estimating the weight of common shapes, but the number of shapes included in Carmona’s tables is unusual.
Obviously, estimation tables are only substitutes for direct weighing, but when that is not an option, accurate tables become a vital tool. It is also obvious that no individual would have access to every size and shape of every gemstone included in comprehensive tables. Many sizes and shapes were measured in quartz or synthetics for the differences in specific gravity. Extrapolation was used to fill in between measured samples.
Frequent users are likely to make their own adjustments to various elements of the tables as they employ them, but their availability in such detail should prove to be exceptionally useful to many in the jewelry industry.
About the author
Charles I Carmona has been active in the mineral collecting hobby and the gem and jewelry trade for over 30 years, from prospecting and mining to gem cutting, wholesale and retail sales, and extensive experience in the appraisal of all types of gemstones and jewelry. As a consultant to attorneys, accountants, banks, government agencies and the gem and jewelry trade, his reputation as an expert has been well established. The need to accurately estimate the weights of mounted gemstones on a daily basis led to this compendium of formulas and tables.
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