With the various means of transportation and locomotion that have existed in the past twenty-three or twenty-four centuries, there is no doubt that the commerce of pearls has varied more or less, but there has ever been, in some part of the world, a great potentate, a great collector or dealer who has influenced the finest gems to gravitate his way. Never has there been a time when some person was not prepared to encourage—and to richly encourage—the sale of fine jewels to him. The history of the commerce of precious stones is a history of travel and exploration, of hardship, pleasure, reward, and sometimes of serious disappointment.
The lesson we derive from these decorative objects of natural beauty and softness—treasured alike by savage, barbarian, ancient warrior, statesman, king, emperor, peasant, bourgeois, magyar, lady, and queen—always carries with it the moral that the gifts of creation are ever prized by some one in every age or place.
The necessary qualifications affecting the value of a pearl are: first, that it should be perfectly round, pear-shaped, drop-shaped, egg-shaped, or button-shaped, and as even in form as though it were turned on a lathe. It must have a perfectly clear skin, and a decided color or tint, whether white, pink, creamy, gray, brown or black. If white, it must not have a cloud or a blur or haze, nor should the skin have the slightest appearance of being opaque or dead. It must be absolutely free from all cracks, scratches, spots, flaws, indentations, shadowy reflections or blemishes of any kind. It must possess the peculiar luster or orient characteristic of the gem. The skin must be unbroken, and not show any evidence of having been polished.
Diamonds and the more valuable precious stones generally are bought and sold by the weight called a carat. This carat, whatever its precise value, is always considered as divisible into four diamond or pearl grains, but the subdivisions of the carat are usually expressed by the vulgar fractions, one fourth, one eighth, one twelfth, one sixteenth, one twenty-fourth, one thirty-second, and one sixty-fourth. The origin of the carat is to be sought in certain small, hard, leguminous seeds, which, when dried, remain constant in weight. The brilliant, glossy, scarlet-and-black seed of Abrus precatorius constitutes the Indian rati, about three grains; the Adenanthera pavonina seed weighs about four grains. The seed of the locust-tree, Ceratonia siliqua, weighs on the average three and one sixth grains, and constitutes, no doubt, the true origin of the carat.
Another[[377]] of the more notable of these weight-units used for precious stones and precious metals is the candarin, condorine, or cantarai, also termed by the Chinese fun or fan, and by the south Indians a fanam, and used all over the Indo-Chinese archipelago. This is by origin a large lentil or pea of a pinkish color dotted with black, about double the size of the gonj, and possessing the same quality of very slight variability of weight when dried. It is probably a variety of the same botanic genus or species as the Abrus precatorius. The value when reduced to absolute standard became a subsidiary part or submultiple of the weight of some local coin, rupee, or pagoda, or a decimal fraction of some local tchen, as in China and Japan.
The following derivation of the word carat is given by Grimm: “Carat. Italian: carato; French: carat; Spanish and Portuguese: quilate; Old Portuguese: quirate, from Arabic qirat, and this from the Greek, κεράτιον.”[[378]]
The carat is not absolutely of the same value in all countries. Its weight, as used for weighing the diamond, pearl, and other gemstones in different parts of the world, is given in decimals of a gram, by the majority of the authorities, as follows:
| Grams | In Grains Troy | |
|---|---|---|
| Indian (Madras) | .2073533 | 3.199948 |
| Austrian (Vienna) | .20613+ | 3.18107+ |
| German (Frankfort) | .20577+ | 3.175514 |
| Brazil and Portugal | .20575+ | 3.175206 |
| France | .2055+ | 3.171347 |
| England | .205409 | 3.169943 |
| Spain | .205393 | 3.169696 |
| Holland | .205044 | 3.16431+ |
| Pearl Grains in Grams | In Grains Troy | |
|---|---|---|
| Indian (Madras) | .0518383 | .799987 |
| Austrian (Vienna) | .05153+ | .79526+ |
| German (Frankfort) | .05144+ | .793878 |
| Brazil and Portugal | .05143+ | .793801 |
| France | .051375 | .792836 |
| England | .051352 | .792485 |
| Spain | .051348 | .792424 |
| Holland | .051261 | .791077 |
Assuming that the gram corresponds to 15.43235 English grains, an English diamond carat will nearly equal 3.17 grains. It is, however, spoken of as being equal to four grains, the grains meant being “diamond” or “pearl” grains, and not ordinary troy or avoirdupois grains. Thus a diamond or pearl grain is but .7925 of a true grain. In an English troy ounce of 480 grains there are 151½ carats; and so it will be seen that a carat is not indeed quite 3.17 grains, but something like 3.1683168 grains, or less exactly, 3.168 grains. Further, if we accept the equivalent in grains of one gram to be, as stated above, 15.43235, and if there be 151½ carats in a troy ounce of 480 grains, it will follow that an English diamond carat is .205304 of a gram, not .205409, as commonly affirmed. The following exact equivalents, in metric grams and grains troy, of the diamond carat as used in different parts of the world in 1882, are given by Mr. Lowis d’A. Jackson: