On March 11, 1908, the metric CARAT of 200 MILLIGRAMS was adopted in Spain as the official carat for diamonds, PEARLS and precious gemstones.

Pearls have become of so much importance to so many dealers that a special form of weight has been proposed for them. This would have a diamond form and not a square form, and it would be stamped "Grain" instead of "Carat." Another set would be stamped in milligrams, the regular milligrams weight with the pearl fraction above it, and they could even be made round so as better to designate the pearl.

The great value of pearls has suggested the making of a gage, called the Kunz GAGE, by means of which round pearls can be very accurately measured. Pearls of a given weight and perfectly spherical form have been weighed and then measured by this gage, and the theoretical diameters as computed from the measurement of a single pearl are in the majority of instances in exact accord with these actual measurements, the occasional variations in the smaller pearls barely exceeding the thousandth part of an inch.

These discrepancies may be due to imperceptible divergences in sphericity or, possibly, to trifling difference in specific gravity.

The new and finer analytical balances weigh to the tenth part of a milligram, the two thousandth part of a carat, the five hundredth part of a grain; but this is not necessary.

If the 200-milligram carat were used, the two hundredth part of a carat could readily be ascertained, and then a short-beam, rapid-weighing balance would answer every purpose and save much time for the dealer who must make many weighing in the course of a day. In an office where thousands of weighings were made in a month, the task was accomplished with such minute accuracy that the margin of error did not exceed one carat during this time!

Rebecca

Antique Jewelry Investor Support team

Reference:

http://www.karipearls.com/carat.html