72 PRECIOUS STONES
The ounce troy (151.42 carats) is used for weighing Baroque pearls, coral, and semi-precious stones.
The Indian (Hindoo) weight rati (or ruttee) equals 0.89062 carat, and one thola is about fifty-seven carats.
The mangelin of Golconda and Visapur was equivalent to one and three-eighths carats.
In
the weighing of diamonds, fractional parts of the carat are divided by
two down to sixty-fourths. Beyond that no division is reckoned.
Pearls
are sold by the grain, although it is not the standÂard grain weight,
but one-fourth of a carat, which is a fraction less that 0.8 of a grain
troy. This carat grain has led to the use of the word in connection
with diamonds. One-half carat stones are called two-grainers;
three-fourths carat stones, three-grainers; those weighing one carat,
four-grainers, and so on.
The
price of pearls is quoted by the grain and reckoned by the square,
according to the size from the base price of a one-grain pearl, as
follows: Given the price at three dollars base, the cost of
different-sized pearls would be:
A
one-half grain pearl at three dollars base would be one dollar and
fifty cents per grain " flat," half of which would be seventy-five
cents, the price of the pearl.
A one-grain pearl at three dollars base would be three dollars per grain " flat," and three dollars for the pearl.
A
two-grain pearl at three dollars base would be twice three dollars, or
six dollars per grain " flat," and two grains at six dollars would be
twelve dollars, the cost of the pearl.
A
four-grain pearl at three dollars base would be four times three
dollars, or twelve dollars per grain " flat," and four times twelve
dollars would be forty-eight dollars, the price of the pearl, and so on.
