An Encyclopaedia of Indian Archaeology v1.c21.s9.t1: 16.9.3 Other metals—gold, silver and lead
An Encyclopaedia of Indian Archaeology v1.c21.s9.t1
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16.9.3 Other metals—gold, silver and lead
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In India the antiquity of this metal goes back to the Harappa [4.9] period. Gold ornaments are known from LOTHAL (Harappa), ROJDI (late Harappa), TEKKALAKOTA (Neolithic-Chalcolithic [4.14.8], Phase I), DAIMABAD (Chalcolithic [4.14.6]), KAUŚĀMBĪ (300 B.C.) and the Megalithic burials [4.17]. Gold foil beads and small gold objects are reported during the early historical period from NEVASA, NASIK, JORWE, PANDU RAJAR DHIBI, VAIŚĀLĪ, NAGARJUNAKONDA, etc. Except in the Harappa period gold was a scarce metal all through. From the Kushan period this metal was no longer scarce and its use in the form of coins was quite popular. Gupta gold coins show excellent gold metallurgy [3.1].
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Gold occurs in two forms: (1) As ‘placer’ metal (alluvial or detrital gold) it is found in the auriferous sands and gravels of a large number of rivers which pass over auriferous rocks, as in Madhya Pradesh, Maharashtra, Bihar (especially the region of Dts Singhbhum and Manbhum and in the valleys of the Subarnarekha river). That alluvial gold-washing was carried out in antiquity is substantiated from the fact that gold dust was paid by the Indian provinces as tribute to Darius the Achaemenid. (2) Important sources of gold in the form of quartz veins or reefs are the Kolar gold mines which produce 99% of India’s gold output. In addition the Hutti gold mines in Dt Raichur, Ramagiri area in Dt Anantapur and Wynaad area in Dt Nilgiri also deserve mention.
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In the beginning gold nuggets were collected from the surface and gold was mined by ‘open cast’ method. A later method used for mining appears to have been ‘fire-setting’, where rock faces were heated and then cracked by throwing water on them. This helped in sinking deep shafts in quartz veins. Stray finds among old workings, two ¹⁴C samples from Hutti and field investigations indicate that shafts through the quartz veins had reached a considerable depth by the beginning of the Christian era. Over 240 m deep anciently worked mines have been recorded at frequent intervals along several km of reefs of the Kolar and Hutti gold mines.
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Considering that gold from Kolar and Hutti gold mines is of light colour (being electrum, a native gold-silver alloy) and similar gold objects have been recovered from the Harappa sites, it has been inferred that the surface collection of gold nuggets had started by the Harappa period. The clustering of Neolithic sites around gold-mining areas and the recovery of gold ornaments from limited excavations of the Neolithic-Chalcolithic site of TEKKALAKOTA and Chalcolithic site of DAIMABAD confirm that the exploitation of these gold mines continued after the Harappa period.
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Small pure metallic nuggets collected from the mining area could be hammered and directly shaped into simple ornaments and need not necessarily have needed the expert services of a goldsmith. But gold mined from quartz veins needed some treatment. The detached rock was carried outside the mine where it was crushed in large stone mortars and finally ground. This powder was washed with water on a sloping surface and gold particles were separated. Alternatively alluvial gold was agitated with water in pans, cradles and sluices, so that earthy matter was floated off and gold particles were retained.
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Gold particles whether obtained from alluvial washing or separated from reef gold were fused into small ingots in clay crucibles over charcoal fire at a temperature of 1063° C.
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In the Harappa period gold ornaments were made both by hammering and casting. The art of drawing gold wires, soldering the metal and making both hollow and solid gold ornaments was known. Hollow conical ear ornaments, corrugated finger rings, large circular gold pendants with axial holes and minute beads show a remarkable skill of the craftsman.
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[An analysis of the gold ornaments such as necklaces, spiral ear-rings and ear ornaments from the MAHURJHARI (Megalithic [4.17.6]) stone circles shows that whereas some are of 99·8% pure gold, several others are a mixture of gold and silver, each contributing nearly 50%. The ornaments were variously made of solid gold wire, gold leaf possibly mounted on a lac base and tubes filled in with lac. The NAGARJUNAKONDA megaliths [4.17.7] have yielded spiral-shaped ear-rings and 35 cylindrical beads of thin sheet gold. An alloy of silver has been used for the manufacture of 18 spacer beads exactly similar in shape to the gold ones. Gold diadems have been found in the urn burials [4.17.9] of ADICHANALLUR].
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The chemical composition of Gupta gold coins shows them to be an alloy of gold (75%) and silver (25%). This alloy has favourable mechanical properties and good castability. It has high ductility, low annealing temperature and extremely easy workability. Twenty-five per cent silver has helped to increase the hardness (160 Vickers hardness no.). The macro-examination of the coins shows excellent embossing on both the sides indicating that striking techniques were well developed.
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Both silver and lead may be dealt with together on account of their common source and metallurgy. The earliest use of these metals goes back to the Harappa period. A silver bangle and a few silver fragments are reported from LOTHAL. 102 silver plates were recovered in association with the Copper Hoards [4.11] from GUNGERIA. The regular use of silver is marked by the introduction of silver punch-marked coins [3.1] by 600 B.C. Lead objects are reported from Harappa sites now in Pakistan but not from those in India. However lead was frequently used in this period for alloying with copper [4.9.1] and its advantage in lowering the melting point and thus easing in casting was fully realized. In the early historical period lead was a common metal, and its objects in the form of spools of coiled strip, wire, nails, antimony rods [18.1] and the like are reported from many sites. Lead was also used for minting coins.
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There are no silver ores in India. Most of the silver is obtained as a by-product of the smelting of lead ores. The major sources of silver and lead have been the argentiferous lead-zinc ores of the Dawdwin mines in Burma and the Zewar mine, Dt Udaipur. Both of these are reputed to have been worked in antiquity. It is quite likely that silver ores were also obtained from Baluchistan, Afghanistan, Iran, etc. A small amount of silver could have come from the gold mines of s. India where this metal is found naturally alloyed with gold and is believed to have been used since the Harappa period.
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But the impurity pattern of Mohenjo-daro silver (the chemical analysis of LOTHAL silver is not available) and punch-marked coins in general shows that their source was argentiferous galena rather than electrum. However silver plates reported from GUNGERIA show 3·70% gold and a punch-marked coin in the Lucknow museum has been reported with 10·53% gold. This could imply that a method of separation of silver from gold was worked out during the Copper Hoard period [4.11].
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The production of both lead and silver was from the same ore—argentiferous galena (basically an ore of lead in which silver occurs as an impurity). Smelting of this ore and extraction of lead from it is one of the simplest metallurgical operations. In ancient times metallic lead could have been obtained by simply heaping the ore on top of the fuel placed on the ground or in a pit. Fused metal, which melts at 327° C, could have run out at the bottom of the heap and was collected. (Reduction temperature of lead oxide is well within 800° C and so smelting could be done easily in a domestic fire using charcoal.)
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Crude lead (base bullion) as obtained above was repeatedly melted and crystallized and lead crystals were removed. This resulted in the concentration of silver as in the modern Pattinson’s process. The remnant of lead was removed by the cupellation process.
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Metallurgical studies of silver punch-marked coins reveal that despite primitive techniques by 600 B.C. Indians could obtain silver of high purity (0·1 to 0·5% lead was the main impurity). It indicates that cupellation was carried out with great perfection. Alloying of silver with copper was deliberate and in correct proportion, giving ease in casting, providing optimum strength and wear resistance. It also economized the metal.
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Allchin, F.R., 1962, in *Jour. Economic & Social History of the Orient*, 5 (for methods of gold mining in ancient India). Bhardwaj, H.C. & Misra, S., 1968, in *Jour. Numismatic Soc. of India*, 30, pp.
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241-51 (for silver coins): 1971, in *ibid*., 33, 123-7 (for Gupta coins).—H.C. BHARDWAJ
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*16.9.4 Slag*. Slag is the refuse material left after the smelting of metallic ores and comprises fused earthy matter. On account of its easy fusibility and low density it is conveniently removed during smelting, the separation being facilitated by the use of flux. It survives in a good condition without much chemical alteration and is of great significance in archaeological metallurgy.
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Smelting of ores was generally done more near mining areas than in habitational settlements. Accordingly enormous quantities of slag of copper, lead and iron are found littered around these areas. Some of them may belong to great antiquity though no definite dates can be assigned to them.
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Copper slag is also reported from such sites as LOTHAI. (Harappa [4.9]), AHAR² (Chalcolithic [4.14.1]), RAJGHAT⁴ and SHAMALAJI (early historical); and iron slag from HASTINĀPURA (PGW), RAJGHAT⁴, UJJAIN, PANDU RAJAR DHIBI, MAHISDAL, SARADKEL and SHAMALAJI (all early historical). So-called glassy slag is reported from NAVDATOLI, MAHESHWAR, NAGARA, NEVASA and KOPIA (all from early historical levels). Slag is reported from a number of ash mound sites [14.3].
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The occurrence of slag is an evidence of local smelting. Its analyses are instructive in that they reveal the contemporary smelting practices, nature of the ores used, percentage of the metal extracted, use of flux and the temperature available. The analyses of (1) copper slag from AHAR² (Chalcolithic), (2) copper slag from RAJGHAT⁴, Pd I (early historical), (3) iron slag (from the same site and level), and (4) slag from KUPGAL (ash mound) are as follows per cent: loss on ignition—in (1) and (2) nil, in (3) 3·14, in (4) 10·5 (by difference); SiO₂—in (1) 38·16, in (2) 39·17, in (3) 16·32, in (4) 62·00; Fe₂O₃/FeO—in (1) 45·32, in (2) 38·72, in (3) 74·43, in (4) 11·00 (combined with Al₂O₃); Al₂O₃—in (1) 5·96, in (2) 12·02, in (3) 4·25, in (4) see above; CaO—in (1) nil, in (2) 5·39, in (3) 1·20, in (4) 8·00; MgO—in (1) 3·02, in (2) 0·62, in (3) 0·45, in (4) nil; MnO₂—in (1) 0·89, in (2), (3) and (4) nil; CuO—in (1) 0·91, in (2) 1·05, in (3) and (4) nil; Ni, in (1), (3) and (4) nil, in (2) trace; SO₃—in (1) 4·14, in (2) 0·20, in (3) and (4) nil; P₂O₅—in 1 and (2) nil, in (3) trace, in (4) 2·5; TiO₂—in (1), (2) and (4) nil, in (3) trace; K₂O—in (1), (2) and (3) nil, in (4) 5·00; C—in (1), (2) and (3) nil, in (4) 1·00. Thus in (1) and (2) chalcopyrite is the main copper ore used and either the ore contained good percentage of silica or silica was added as flux. About 1% of the metal is left in the slag which shows that extraction was fairly good. In (3) very rich ore was used but as much as 74% of the ore was left unsmelted. It implies that iron technology was not yet fully evolved and the requisite temperature was not available. The so-called slag reported from the ash mounds is not of iron but is the product of continual burning of cowdung.
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Bhardwaj, H.C., "Aspects of Ancient Indian Technology", Ph.D. *thesis*, Banaras Hindu Univ.; in Agrawal, D.P., & Ghosh, A., ed., 1973, *Radiocarbon & Indian Arch*., Bombay. Hegde, K.T.M., in Sankalia, H.D., *et al*., 1969, *Excavations at Ahar*, Poona. Mujumdar, G.G., & Rajaguru, S N., 1966, *Ashmound Excavations at Kupgal*, Poona. For other sites see respective entries in vol. II.—H.C. BHARDWAJ
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*16.9.5 Tin*. The tin-bearing localities in India are in Dts Hazaribagh, Dharwar, Palanpur, Champaner, Bhilwara, Bastar, Almora and Pithoragarh (Chakrabarti, 1979) and a few other localities elsewhere of which no precise information is available.
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While there is no evidence of the occurrence of tin in any pre-Harappa context it is a regular constituent in the Harappa copper/bronze assemblage, taking 1% or more as an indication of its deliberate use, the percentage ranging from 1·2 to 26·9 at Mohenjo-daro (Marshall, 1931, pp. 480-2, p. 484; Mackay, 1938, p. 479), 3·60 to 10·45 at Harappa (Vats, 1940, p. 378) and 2·60 to 11·07 at RANGPUR (Rao, 1963, pp. 152-3). Agrawal, 1969-70, is of the view that the tin-bronze is more abundant in the upper levels of Mohenjo-daro than in the lower ones, but the limited data may not justify such conclusion. [See also 16.9.1.]
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On the Chalcolithic [4.14] sites, while AHAR² has no tin, a fact which need not be overemphasized, NAVDATOLI, NEVASA, JORWE, CHANDOLI and SONPUR I A show a low range of tin (Agrawal, 1969-70; 1973, p. 187). Previous meagre data show that the Copper Hoards have tin in proportions ranging from 3·83 to 13·3% (Smith, 1904, pp. 229-44), but subsequent analysis of some Copper Hoard [4.11] objects has not revealed tin in any worth-mentioning quantity. An ADICHANALLUR urn burial [4.17.9] object however shows a high percentage of 23% (Rea, 1915, p. 3).
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The bulk of evidence of the early historical period comes from Taxila where the tin percentage is usually high (Marshall, 1951, pp. 567-9). So is it in objects from the earlier historical levels of PRAKASH (Athavale in Thapar, 1964 and 1965, pp. 131-5) and the coins from KAUŚĀMBĪ (Prakash and Singh, 1968). The 18 late historical bronzes at NĀLANDĀ that have been examined have a range of 1·15 to 23·68% (Lal, 1956, pp. 53-7), while one bronze from Kurkihar has 13·00% (Shere, 1961?). A Gupta bronze in the Cleveland Museum has 16·40% (Czuma, 1966, p. 70). but some 12th-century s. Indian bronzes have a low content of tin.
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In all cases the tin ores available within the limits of India might have been the source though for the Harappa sites Khorasan and the area between Bukhara and Samarkand, where Harappan movements have now been established, might have been an additional source.
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Agrawal, D.P., 1969-70, in *Purātattva*, 3; 1971, *Copper Bronze Age in India*, New Delhi. Chakrabarti, D.K., 1979, in *Man & Environment*, 3, pp. 71-4 (for tin in early India). Czuma, S., 1970, in *Bull. Cleveland Museum of Art*, Feb., pp. 55-67. Lal, B.B., 1956, in *AI*, 12. Mackay, E.J.H., 1938, *Further Excavations at Mohenjo-daro*, Delhi, 1. Marshall, J., (ed.), 1931, *Mohenjo-daro & the Indus Civilization*, London, 2; 1951, *Taxila*, Cambridge. Prakash, S., & Singh, R., 1968, *Coinage in Ancient India*, New Delhi. Rao, S.R., 1962 & 1963, in *AI*, 18 & 19. Rea, A., 1915, *Catalogue of the Prehistoric Antiquities from Adichanallur & Perumbair*, Madras. Shere, S.A., 1961 (?), in *Bronze Images in Patna Museum*, Patna. Smith, V.A., 1905, in *Indian Antiquary*, 34. Thapar, B.K., 1964 & 1965, in *AI*, 20 & 21. Vats, M.S., 1940, *Excavations at Harappa*, Delhi.—D.K. CHAKRABARTI
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the top is flat. The profile is generally concave, tapering or vertical and the base is invariably convex which is necessary to retain the convexity of the finished vessels. Short, stumpy and conical dabbers are also known.