| DIAMOND CARATS | ||
|---|---|---|
| Grams | Grains Troy | |
| Turin | .2135 | 3.29480 |
| Persia | .2095 | 3.23307 |
| Venice | .2071 | 3.19603 |
| Austro-Hungary | .2061 | 3.18060 |
| France (old) | .2059 | 3.17752 |
| France (later) | .2055 | 3.17135 |
| France (modern) | .2050 | 3.16363 |
| Portugal | .2058 | 3.17597 |
| Frankfort and Hamburg | .2058 | 3.17597 |
| Germany | .2055 | 3.17135 |
| East Indies | .2055 | 3.17135 |
| England and British India | .2053 | 3.16826 |
| Belgium (Antwerp) | .2053 | 3.16826 |
| Russia | .2051 | 3.16517 |
| Holland | .2051 | 3.16517 |
| Turkey | .2005 | 3.09418 |
| Spain | .1999 | 3.08492 |
| Java and Borneo | .1969 | 3.03862 |
| Florence | .1965 | 3.03245 |
| Arabia | .1944 | 3.00004 |
| Brazil | .1922 | 2.96610 |
| Egypt | .1917 | 2.95838 |
| Bologna | .1886 | 2.91054 |
| International carat | .2050 | 3.16363 |
| Proposed new international carat | .2000 | 3.08647 |
Recalculating the above figures into pearl grains we have:
| PEARL GRAINS | ||
|---|---|---|
| Grams | Grains Troy | |
| Turin | .053375 | .823700 |
| Persia | .052375 | .808267 |
| Venice | .051775 | .799007 |
| Austro-Hungary | .051525 | .795150 |
| France (old) | .051475 | .794380 |
| France (later) | .051375 | .792837 |
| France (modern) | .051250 | .790907 |
| Portugal | .051450 | .793902 |
| Frankfort and Hamburg | .051450 | .793992 |
| Germany | .051375 | .792837 |
| East Indies | .051375 | .792837 |
| England and British India | .051325 | .792065 |
| Belgium (Antwerp) | .051325 | .792065 |
| Russia | .051275 | .791292 |
| Holland | .051275 | .791292 |
| Turkey | .050125 | .773545 |
| Spain | .049975 | .771230 |
| Java and Borneo | .049225 | .759655 |
| Florence | .049125 | .758112 |
| Arabia | .048600 | .750010 |
| Brazil | .048050 | .741522 |
| Egypt | .047925 | .739595 |
| Bologna | .047150 | .727635 |
| International | .051250 | .790907 |
| Proposed International | .050000 | .771617 |
With the present system of diamond carats and pearl grains it is necessary to keep two entirely different sets of weights or to resort to troublesome calculations. The stock-book of a jeweler, at the present time, will contain the following fractions, expressing the weight of a single pearl: ½, ¼, ⅛, 1⁄16, 1⁄32, 1⁄64, when the weight could be much better stated as 63⁄64 of a carat. It requires but a glance to see how much easier this would be. Certain dealers have therefore proposed the use of sets of fractions arranged in a similar way. In this manner a stock-book can be kept much more easily and with greater precision. Others, again, have adopted a decimal notation of the fractions of a carat, which is even more simple and feasible, since the common fractions ½, ¼, ⅛, etc. can be expressed as .5, .25, .125, etc., of a carat, this being either a carat of .2053 of a gram or the English carat of .20534 of a gram.
On the other hand, an agreement was arrived at, as the result of a conference between the diamond merchants of London, Paris, and Amsterdam, by which the uniform weight of a diamond carat was fixed at .205 of a gram, making the pearl grain .05125 of a gram. This standard, which was suggested in 1871, by a syndicate of Parisian jewelers, goldsmiths, and others dealing in precious stones, was subsequently (1877) confirmed. But there is still a lack of uniformity in the standard by which diamonds and pearls are bought and sold, and very serious discrepancies exist in the sets of carat weights turned out by different makers, although the international carat is almost universally used.
At the International Congress of Weights and Measures held at the World’s Fair at Chicago in 1893, the writer suggested that the carat should consist of 200 milligrams, so that ½ of a carat would be 100 milligrams and ¼ of a grain would be 12.5 milligrams. This would mean 5 carats or 20 grains to a French gram, and 5000 carats or 20,000 pearl grains to a French kilogram. This would depreciate the present diamond carat or pearl grain only about one per cent., and it would do away with the needless series of carats and grains of the many nationalities. It could be simply explained to any private individual in any country, especially as there are only two countries which do not use the metric system.
This carat has been earnestly indorsed, its introduction advocated, and its merits clearly shown, by M. Guilliame, of the French Bureau des Arts et Metiers, whose energetic work has found a reasonable cooperation, in this country as well as in Europe, in introducing what will be a scientific, logical, comprehensive, and possibly the final and international carat; and any ancient, obsolete, or foreign carat can be readily reduced to this carat once the metric value of the former is computed.
The Association of Diamond Merchants of Amsterdam has already, to avoid confusion, fixed the value of the carat (17th October, 1890) at 1 kilogram = 4875 carats, or 1 carat = 3.16561 grains troy = 205.128 mg. One pearl grain = .7914 grains troy = 51.282 mg.; but the association has decided that, in case of litigation, these values shall be determined by appointed bureaus, which would express them in grams and milligrams, a most important and valuable decision, as the gram and the milligram will always be known as weights of constant value.
In view of the difficulty of inducing the abolition of the carat in different countries, the German Federation of Jewelers decided to petition the imperial government for authority to use the carat, in order that it might be legally recognized. Such a proposition not being in accord with the German laws in force on the subject of the metric system, it was proposed to substitute for the carats then in use one carat only, weighing two hundred milligrams. This proposal was very favorably received in trade circles and may be taken into consideration by the International Committee of Weights and Measures. The Commission des Instruments et Travaux, to which this proposition was referred, recommended its adoption to the committee in the following terms:
“The Commission recognizes that it would be very desirable that the unit of weight of precious stones (the carat) which varies in different countries, should be made uniform, and should be reduced to the nearest metric equivalent. The weight of 200 mg., which is very close to the carat most in use (205.5 mg.), would seem to be the best for this purpose. The Commission believes that there can be no objection to this standard of 200 mg. being called ‘the metric carat’ in order to facilitate the abolition of the old carat.”