104 GENERAL CHARACTERS OF PRECIOUS STONES 



milligrams is equal to 3-203 milligrams. The fourth part of a carat is known as a grain, 

 being, however, not an ordinary grain but a " diamond-grain," " pearl-grain," or " carat- 

 grain " ; it is a unit but rarely used. In France 144 carats equal one ounce. 



The practical inconveniences which result from the discrepancies between the weight of 

 a carat in different countries can easily be imagined. So firmly established, however, is the 

 use of this unit in almost all civilised countries, that there seems no prospect of replacing it 

 by the more convenient gram of the metric system. The change to grams could be effected 

 with no great confusion, since the weight of half a carat very nearly corresponds in all cases 

 to 100 milligrams or ^-^ gram. The gram, however, finds very little favour with dealers in 

 precious stones, although in Germany since 1872, in Austria since 1 876, and in Holland for 

 some time, it has been the lawful unit of weight for precious stones. In 1871, and again in 

 1876, a syndicate of Parisian jewellers proposed that the carat should universally have the 

 value of 205-000 milligrams, a value it has always had in Leipzig and in the Dutch East 

 Indies. This proposal has met with considerable favour, and it is probable that before long 

 this value for the carat will be universally accepted, and that other values will fall into 

 disuse, since the jewel-dealers of London and Amsterdam, which are the centres of the trade, 

 are at one with their Parisian colleagues in this matter. At the same time, it is proposed 

 to subdivide the carat according to the decimal system instead of the present cumbrous 

 and inconvenient division into sixty-fourths. 



In England dealers in precious stones, especially the less valuable so-called semi-precious 

 stones, sometimes make use of troy weight, as it is also employed for precious metals. An 

 ounce troy (480 grains) = 31-103 grams = 151-707 carats (of 205 milligrams). This carat 

 then is equal to 3-165 grains, and inversely a grain = 0-316 carat. Further, a grain troy, 

 avoirdupois or apothecaries', is equal to 1 -264 " carat-gi-ains," " pearl-grains," or " diamond- 

 grains " ; and one " diamond-grain " is equal to 0-791 grain troy. The word grain is 

 therefore ambiguous, and a weight given in grains is likely to lead to confusion and error, 

 unless it is definitely known what system of units is referred to. This confusion, however, 

 is confined to British weights, for in no other country is the grain troy used for precious 

 stones. 



Some other units of weight of little importance are in local use at certain places where 

 precious stones are found, 'fhe more important of such units will be briefly mentioned here 

 since they are sometimes to be found in books of travel and in old descriptions of precious 

 stones, as well as in more recent reports of the occurrence of precious stones in various 

 countries, and there is often difficulty in obtaining information concerning such units. 



In Brazil the weight of gold and precious stones is estimated in oitavas, an oitava 

 being ^ ounce, and 128 oitavas going to the pound. The oitava, which corresponds in 

 weight to 17|^ carats (sometimes given at 18), is subdivided into thirty-two vintems. Some- 

 times, however, the carat-grain is used as a subdivision of the oitava. Since four carat- 

 grains are equal to one carat, one oitava is equal to 70 (or 72) grains. 



While this Brazilian unit of weight has a direct connection with the carat, the unit 

 used in India, especially in former times, is quite independent and distinct from it. This 

 Indian unit varies in diff'erent localities, aiid has also varied in value at different periods. 

 The Indian unit of weight, used principally in Sambalpur, is the masha ; it is subdivided 

 into eight ratis, a rati being the weight of the scarlet and black bead-like seed of the plant 

 Ahrus precatorius ,- the rati is itself subdivided into four dhans. The value of a rati varies 

 at diff'erent places and times between 1-86 and 2-25 grains troy. On an average, therefore, 

 one rati = 2 grains troy = 2^ carat-grains = about f carat. In Nagpur in 1827 one rati was 

 actually equal to 2-014 grains troy ; but at the present day it is usually equal to 1^ or 1-88 



