Minerals and Metals in Ancient India v1.c24.s1.t3: Silicate Gem Minerals
Minerals and Metals in Ancient India v1.c24.s1.t3
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Silicate Gem Minerals
v1.c24.s1.t3.1
Silicates are conventionally classified in terms of Si : O ratio in the network: 3-D network (1 : 2), sheet structure (2 : 5), double chain structure (4 : 11), cyclosilicate (1 : 3), individual tetrahedra (1 : 4) etc. We would also continue our discussion under the above classification system.
v1.c24.s1.t3.2
The most important sub-group having Si : O ratio 1 : 2 or 3-D structure is quartz and related minerals which has been discussed earlier. The other important sub-group is the feldspars.
v1.c24.s1.t3.3
The feldspar called moonstone came from the gem-gravels of South-Western Sri Lanka, specially Dumbara. Warmington doubted whether it could be Pliny’s ‘astrion’ or his ‘ceraunia’, and suggested that it could be his ‘selenitis’. The other mineral in this sub-group, lapis lazuli came from the ancient mines at Firgamu in Badakshan by caravans through Afghanistan to Barbarikon (near Karachi), and the Romans took it as an Indian product.
v1.c24.s1.t3.4
Jadeite, Nephrite and Asbestos belong to the Actinolite family. The first two might have travelled from Turkestan and China to the West. But we cannot say with certainty whether the materials were known as ‘iaspis’ or ‘yashm’ as suggested by Warmington, and whether much of this commodity passed through the territories of the Bactrian and Kuṣāṇa kings in India for the Romans. The Romans obtained incombustible fibrous mineral called asbestos or chrysotile, ‘valued it as highly as best pearls, and had it woven into wicks, handkerchiefs and shrouds’. They must have obtained their supplies from Badakshan, Afghanistan, which also seems to have been the source of the hand-towels of asbestos sent by king Aśoka to his counterpart in Sri Lanka on 247 BC.
Cites (1)
- Naturalis historia — C. Plinius Secundus, Latin