Minerals and Metals in Ancient India v2.c43.s3.t6.5
Minerals and Metals in Ancient India v2.c43.s3.t6.5
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v2.c43.s3.t6.5
The varieties of zircon can be distinguished from other gems through their remarkably high specific gravity (4.61-4.82) and characteristic hardness 7-1/2 which is slightly more than that of garnet (hardness 7-1/4 and sp. gr. 3.6-3.7) and much less than that of diamond (hardness 10 and sp. gr. 3.52). We have mentioned earlier that the heavier or ‘Matura variety of diamond’ was considered to be impure or fake diamond (AM, 49-52); this came from the gem gravel of Sri Lanka as jargon.