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(a) To this group belong about 15 varieties of quartz with
a hardness of about 7. They are agate, amethyst, bloodstone or heliotrope, cairngorm, carnelian, cat's eye, chalcedony, chrysoprase, citrine, jasper, onyx, plasma, quartz, rock crystal and sardonyx.
Orthoclase, oligoclase, labradorite, turquoise and hauyne with a hardness of about 6 also belong to this group of precious stones.
Cordierite or dichroite, aqua-inarine, emerald and beryl with a hardness of about 7.5 to 8 are the more valuable stones of this group.
2nd Those that have a density of about 2.9 to 3.5 and hardness
There are about half a dozen stones of this group which are not so valued as gems except chrysolite or peridot and tourmaline (red, green and blue varieties) each of a hardness of about 7 to 7.5 respectively.
3rd-Those that have a density of about 3.5 to 4.5 and a hardness of about 7.5 to 10 and belong to the class of the most highly valued gems. They are arranged in order of their hardness and value as below
Diamond, hardness 10 (b) Ruby, Sapphire, Oriental Emerald, Oriental Amethyst
and Oriental Topaz-hardness 9 (c) Chrysoberyl-hardness 8-5 (d) Spinel-Ruby and Topaz-hardness 8 (e) Almandine and Pyrope, red Garnets, harndess about 7.5 (1) Hyacinth, Jargon, and Zircon-hardness about 5
Note-- 2 minerals of a low density of about 2 to 2.4 and a low hardness of about 5 to 6.5 deserve some mention, however, ou account of their being highly valued. They are the Noble or French opals and Lapis Lazuli.
The Noble opal ranks among the most highly priced gems on account of its beautiful play of fire like colours: red, yellow, green and blue; moreover it is very ditlicult to cut opal as it is very brittle. Lapis Lazuli is also a beautiful blue stone, though softer and of much less value than the opal.
Fala, , , , 96411, gura, , afo, 1947, 4*1, hate, til, Fa, a, a, a, a, u 1:1, at 5a, Eflk, c6 etc. are some of the Indian names of precious stones. Those interested in their study are referred to actical or more especially to get hela& wherein will be
| SR No. | 008438 |
| Book Title | Aparajitaprucchha |
| Original Sutra Author | N/A |
| Author | B Bhattacharya |
| Publisher | Oriental Research Institute Vadodra |
| Publication Year | |
| Total Pages | 810 |
| Language | Sanskrit, Hindi |
| Classification | Book_Devnagari, Culture, & Art |
| File Size | 12 MB |