Agate Origin
Posted on June 17, 2008
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Agate is found in cavities, often irregular in shape, and also in holes in old lavas. It has resulted from the deposits of silica being thrown out of solutions, the shape of the bands following the shape of the cavities. Often, the layers suggest the outline of an almond, many beautiful designs being seen.
Agates are found as rounded pebbles in some areas. In India, for instance, where they are locally called akik, the ground is worked by digging pits to a depth of 20 to 70 feet. These pits cave in during the wet weather, so that fresh excavations are made each season. This area, situated in the Rajpipla State, has been worked for a great many years, and Limodra and Cambay are the two centers in which cutting and treating the stones for color are concentrated.
Occasionally, agates are found which show a remarkable display of colors. These are called iris quartz, or rainbow quartz, and such material has been found in Oregon, U.S.A. The stone is made up of a great number of alternately placed bands or layers, and these act as a prism, thus producing the beautiful range Of spectrum colors. Such effects are quite natural, although they are not evident until thin slices are cut and polished. Considerable skill in cutting is required so that the brilliant effect is brought out to the best advantage.
Another peculiar type of agate is sometimes found in Burma, near Mount Popa, some 85 miles north-west of Malanda. These stones are a pure, opaque white, occasionally tinged with black and yellow, or with alternately shaded bands. They are found in the neighboring volcanic alluvium. When some of these stones are cut across the bands, they show a figure which resembles a Burmese pagoda, and good specimens of such a nature are sold at appreciable prices in the country of origin. The stones are worked at Kyaukpadaung and find their way to religious shrines, not being used as personal ornaments since, to the Burmese, the pagoda is an object of religious veneration. Fine specimens of these “Pagoda stones” are rare. Some are artificially colored, like the ordinary agates. They can be used for 1 ct engagement rings.
On account of the varying degrees of porosity of the different layers, artificial staining results in a deepening or total alteration of the natural pale shades. Deep blues and greens, as well as the black and white onyx, are obtained by chemical treatment, and the rough material which is the most suitable for staining obtains the highest price. The staining and treatment of agate is an important industry in Idar-Oberstein, to which German district it is almost solely confined. The originators of this process were Italians, but the secret of the treatment is said to have been conveyed to a German by an Italian while both were imprisoned in Paris. The Germans have since developed and extended the methods, and these call for much patience and skill.
The natural occurrence of the rough stone in the Nahe valley was of great assistance in the furthering of the growing industry, but the local material was rapidly exhausted. The discovery of new finds in Brazil by German emigrants came at an opportune moment. Huge quantities of splendid material were shipped to Germany, and these and other varieties of quartz have been sent at almost regular intervals, except during time of war. Remarkable deposits of magnificent sardonyx are found in Brazil, although the largest agate diggings at present are probably those in the Catalan district of Artigas, Uruguay.
Before the war, the rough stone was shipped from South America to Hamburg, and then sold by auction in Idar-Oberstein, stone merchants being the chief purchasers. After sorting according to market requirements, the stones were given out to workers, who shaped, polished, and drilled the material as directed. The merchants then had the finished stones mounted as jewelry, cabochons in rings, brooches, etc., but larger pieces and slabs were made into inkstands, blotters, clock faces, knife handles, calendars, and similar articles.
The actual lapidaries seldom marketed the finished stone direct, their work being regulated and paid for by the merchants. Their trade was world wide, and agate mounted goods were exported to every country. They found much prominence in coastal and spa resorts, where tourists and holiday-makers were often offered these articles as being made from local stones. Besides Brazil and Uruguay, many fine agates come from India (the Deccan region), Canada (Ontario), and the U.S.A. Fine moss agates also come from India.
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