Emerald in India
Emerald, the most valuable of all precious stones, is a transparent variety of beryl (3 BeO.Al2O3.6SiO2) with the well-known emerald-green colour. Other gemstone varieties of beryl are aquamarine, the sea-green and bluish stones; yellow beryl or heliodor, the yellow variety; aquamarine chryolite, the yellowish-green variety; the morganite, the pinkish variety.
All owe their beauty to their colour and transparency. But their dispersion is low, lacking brilliance like diamond.
In nature, fine, unflawed emeralds are rate, and large unflawed stones are almost unknown. But large flawless aquamarines are common.
Occurrences of Emerald Mines in India:
In the Ajmer-Udaipur belt, emerald mines are confined to the upper fringes of the pegmatite which intrude the biotite-actinolite schist and amphibole-garnet schist. Pockets of emerald are found in these rocks at the contact zones of pegmatite. Since reserves of emerald are dwindling, search for locating new pockets of emerald deposits in the two old mines in the districts of Ajmer and Udaipur are being carried out by the mine owners.
There are a few working mines in Rajasthan, the more important ones being at Rajgarh and Bhubani in the Ajmer district and at Tikahi in Udaipur district. Mining for emerald in India was initiated in the forties and enlarged after Independence. Uptil now (1990), production of uncut emerald in India has gone up to about four lakhs carats, but the amount of cut stones is only about 80000 carats.
Mining in Rajasthan is manual by opencast methods at shallow depths. The crystals, as and when collected, are sorted out according to size, shape and quality. Crude emerald is sold by public auction from time to time.
Transparent and attractive colour portions are separated from the crystals generally by using a wire saw and suitable abrasive power. Cutting, processing and polishing requires special; techniques. Jaipur in Rajasthan is an important center for cutting and polishing emerald. Emeralds are usually given step-cut or cabochon-cut.
Recently, a hundred-per-cent export-oriented cutting and polishing unit for emerald has been set up in Jaipur, to be run by the Government.
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