The carat, is a unit of mass equal to 200 mg or 0.00643 troy oz, and is used for measuring gemstones and pearls.
When the word “carat” sounds, our contemporary understands: it is either a measure of the weight of precious stones (one carat is 0.2 grams); or about the testing of gold accepted in Britain (pure gold conditionally contains 24 carats).
In the old days, the concept of karate was interpreted much more broadly, and it was much more difficult to use the term.
In the beginning a tree grew...
... And the tree was ceratonia. The fruits of ceratonia - bunches of long, curved pods resembling goat horns with seeds of the same size and weight - are loved by the people for their sweet taste and chocolate aroma. The ancient Romans, marveling at the natural uniformity of the seeds of ceratonia, introduced a mass measure equal to one seed of ceratonia into circulation. As weights, of course, the seeds themselves were used.
Carat is also a modified serátiοn, which in Greek means “like a horn”, and in modern sounding has become “ceratonia”. The size of the Roman carat was 0.189 grams - but not everywhere this value was maintained.
Different countries - different carats
Ceratonia does not grow everywhere, but where it grows, it differs in the size of the seeds from the fruits of other regions. How else to explain the difference observed in the definition of carat right up to 1907? The Arab carat, recognized in Mesopotamia, was 0.2232 grams. In Egypt, Syria and Arabia, the carat weighed only 0.195 grams: apparently, ceratonia grew in these, giving small seeds.
On the territory from the southern coast of the Black Sea to the northern borders of Syria, the carat weighed more - 0.204 grams. In England, until the end of the eighteenth century, the size of the carat ranged between 205.3 and 205.4 milligrams - which led to a flurry of continental jewelers. In general, carats weighing from 0.1885 to 0.2135 grams were in use, and discrepancies could be observed even within the same jewelry and shopping center.
And finally, in 1907, in Paris, at a representative forum of metrologists, it was decided to simplify the situation by equating a carat to two hundred milligrams, which in digital writing looks like 0.2 g or 200 mg.
Jewelers wiped perspiration from their foreheads and sighed in relief: an attempt to standardize accounting weight units was a success! They had made similar efforts before, but with the introduction of the same grain, they fell into the same trap. Gran, designed to replace carats exotic for the northern regions, was equated to the mass of barley kernels; but barley is different everywhere!
Karate is not a brother!
England, which hates everything French - and the metric system of measures was invented by the French - decided to conduct the assay business in a decimal (not decimal) basis. And to further confuse the unfortunate inhabitants of the continent, a fractional measure of the concentration of gold in the alloy was called ... also a carat!
One assay carat is one twenty-fourth gold in the alloy. Nine-carat gold is an alloy, the amount of gold itself in which is calculated by the formula: product weight in grams: 24 x 9 = number sought. In eighteen-carat gold, pure gold is 18:24 or 3: 4, that is, three quarters. Just the same! Especially for those who easily operate with shilling and pence. True, it still does not do without grams...
The only thing the French were able to do in their Chamber of Weights and Measures was to force the British to designate weight and assay carats in different ways. Weight carat is ct, assay carat is K. In England, they mockingly laughed at the French innovation - after all, the meaning is clear about which karate in which case we are talking about, why invent some notation, but ultimately agreed.
Weight carat is not easy either
The introduction of rounded to 200 tons of carats also did not go quickly. It took the global jewelry community a quarter century to get used to the idea of a convenient karate in computing. True, the previously made inserts began to weigh more - after all, the new carat basically lost some weight.
So there is nothing surprising in the fact that today the weight carat has been divided into one hundred points, and the mass of especially valuable stones (especially small diamonds) began to be expressed with high accuracy.
Weight and size of stone
The consumer does not really care how many carats and points his stone weighs. It is much more interesting to visually imagine the size of a faceted gem, because the amount of light passing through the crystal depends on the area of the faces.
In addition, different minerals have different densities, and a three-carat ruby does not match the size of a three-carat topaz. For sophisticated lovers of faceted gems, tables have been compiled in which the shape of the cut and the weight in carats are compared with the geometric dimensions of the stone.
Unfortunately, the accuracy of such tables is small: manual cutting allows very significant deviations of the shape of the product from the theoretical ideal. And the density of the mineral is not always the same: for example, one cubic centimeter of pomegranate can weigh three and a half, and all four grams.
Thus, the mass of stone expressed in carats is an important, but far from determining its aesthetic value and monetary value characteristic.
