| 1851 - 520 pages
...exposure to heat, the amethyst becomes white and opalescent, its blue colour totally disappearing. The best amethysts are brought from Cambay, in India, from Siberia, Ceylon, and Persia ; but inferior sorts are also found in Sweden, the Hartz, Bohemia, Pennsylvania, at Oberstem ¡u Germany,... | |
| Robert Hunt - Industries - 1862 - 1068 pages
...0-0123 magnesia, and 0-0418 soda; and he considers the colour owing to a compound of iron and soda. The best amethysts are brought from Cambay, in India...inferior transparency and hue, they occur in Sweden, Brazil, the Hartz, Bohemia, Transylvania ; in agate balls at Oberstein, in Germany ; in large crystalline... | |
| John Michels (Journalist) - Science - 1887 - 470 pages
...purplish violet hue, is the most valuable. The best amethysts are brought from Cambay in India, and from Siberia, Ceylon, and Persia, where they are found...lining the cavities of geodes and in rolled masses. The chief supply of the blue turquoise is drawn from the peninsula of Sinai, the great mining district... | |
| John Michels (Journalist) - Science - 1887 - 352 pages
...purplish violet hue, is the most valuable. The best amethysts are brought from Cambay in India, and from Siberia, Ceylon, and Persia, where they are found both lining the cavities of géodes and in rolled masses. The chief supply of the blue turquoise is drawn from the peninsula of... | |
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