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Jargoon

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JARGOON.
119
It is always found in a crystallized state ; its crystals are seldom in the octahedral form ; they are generally modified prisms.
It is sufficiently hard to mark quartz, but can be marked by the topaz. It does not melt under the action of the blow-pipe, and it loses its colour when exposed to heat.
The natural white jargoon is rare, but when rendered colourless by fire it is called diamond jargoon ; and with rose-cutting, it is used as a jewel.
This stone resists the file ; but though hard, it crum­bles easily. Its specific weight is 4-78. Analysed, it yields
It possesses double refraction in a very nigh degree.
Its cleavage resembles that of the diamond.
Besides the jargoon of Ceylon, there is the inferior or Western stone, which is found in the Trapp rock, near Lisbon ; in the masses of sienite in the county of Galway ; at Expailly in France ; at Leonedo in the province of Vicenza, and in the auriferous sands of the shifting district of Lombardy.
Since jargoons of a large size are seldom found, those in commerce acquire a certain price, although never extravagantly high. A very fine pure olive jargoon, of -012 mètres square, is worth 100 lire ; one less pure, of another colour yet of equal size, costs 25 lire.
Gagat or Greek Jet Page of 243 Jargoon
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