GOLD

Gold During the Classical Period

There has been considerable discussion by classic scholars about the identity of chrysocolla. The modern chrysocolla is a copper silicate, and Pliny may have meant this mineral in some cases; more generally, however, the mineral in question was probably malachite or azurite, the green and blue copper carbonates. The reference to the precipitation mechanism as due to winter cold follows from the ancient idea that many minerals were congealed (frozen) from water analogous to the formation of ice. This passage is one of the first references in the geological literature to oxidation phenomena in mineral (gold) deposits.

The last of the classical Roman writers to briefly refer to gold deposits was Seneca (A.D. 3-65) contemporary of Pliny and tutor to Nero. In his Quaestiones naturales he says in (an interpretative) translation: "In the earth there are some kinds of moisture that harden when fully formed. From these arise all metalliferous deposits from which our avarice seeks gold and silver." This passage suggests that Seneca followed Theophrastus in his view of the origin of gold (deposits) from water.

Early Indian (Hindu) manuscripts mention gold in many contexts but deal only in the simplest of generalities with the origin of the various types of deposits from which the precious metal was obtained. The Rig- Veda, first of the books of the sacred Sanskrit scriptures of the Hindus, composed about 1500 B.C., contains several references to gold and silver but gives only the barest details about the geology of the metals (Ray, 1904, 1925; Bhagvat, 1933). In the Arthashastra of Chanakya or Kautilya (fourth century B.C.) there are further details about gold and silver, but these are concerned principally with the mining, metallurgy, and testing of the two metals. Mention is made, however, of the occurrence of gold ores in mountains and of the different types of auriferous ores - unmixed yellow (probably pyritic ore?), red and reddish yellow (limonitic ore?), and some with a bluish colour on fractures (oxidized copper sulphide ore). Nodules (nuggets) and needles of gold are also described from placers. Several colour types of gold are mentioned -that with a blue shade, silvery (electrum), thorn-apple like (red), and pure (the colour of the pollen of the lotus). The early Indian peoples mined gold extensively from bedrock deposits and obtained the metal from placers in many of the rivers of the Indian Peninsula. Mining of the bedrock deposits was carried out principally in the oxidized zones of auriferous veins and disseminations in sheared zones and iron-formations, as is evident from very ancient workings in the famous Kolar field in south India. Some of these workings probably provided gold to the early Indus Valley civilization of 4000-3000 B.C. (Ray, 1948).

Allchin (1962) has reviewed the evidence of early gold mining in India and the methods employed in winning the precious metal. He has concluded from archaeological evidence and C-14 dating that placer mining in India was widespread long before the Christian Era and that large-scale bedrock mining (principally in the oxidized zones but also in some cases in the hard rock) in southern India began with the Mauryan colonization of the Deccan about the end of the fourth century B.C. The Hutti and Kolar fields appear to have been first prospected and mined about the beginning of the Christian era.

It seems strange that the Greeks, Romans, and Indians never developed any precise scientific theories on the origin of gold and other types of deposits despite the fact that gold was mined from its principal deposits (excluding the quartz-pebble conglomerates) throughout their empires for many centuries. It has been said that the Roman in general, and the Roman (mining) engineer in particular, was a very practical man and not given to speculation and theories; the same can be said of the Greek but only in part. Natural phenomena interested the Greeks but their philosophers were concerned more with speculations on the great manifestations of nature rather than with mundane things such as gold veins. Another factor, it is said, revolves about the use of slaves in Greek, Roman, and Indian mining ventures. To engage in the earthy tasks of mining (and geology) was deemed to be below the elite and generally considered to be disparaging of one's station in life. Therefore, Greek, Roman, and Indian writers provide little if any observational detail on geological and geochemical processes. Their knowledge of minerals was limited to only a few species and their familiarity with rocks was essentially negligible. Therefore, they could not have logically evolved any systematic theories for the origin of (gold) veins and other types of deposits.

REFERENCES AND SELECTED BIBLIOGRAPHY

For better and more look to Boyle R. W., the best research on gold!
Boyle R. W., 1979, The geochemistry of gold and its deposits, Canada GeoL Survey Bull. 280, 584p.

Agricola, G., 1556. De re metallica, Basle. H. C. and L. H. Hoover, Transl., Mining Mag., London. 1912, 637p.
Barba, A. A.. 1640. El Arte de los Metales, Madrid. (Trans. by R. E. Douglass and E. P Mathewson as The Art of the Metals, John Wiley & Sons, New York, 1923, 288p.)
Biringuccio, V., 1540. Pirotechnia, Venice. C. S. Smith and M. T. Gnudi, Trans., M.I.T
Adams, E D., 1938. The Birth and Development of the Geological Sciences, Williams & Wilkins, Co., Baltimore, 506p.
Allchin, E R., 1962. Upon the antiquity and methods of gold mining in ancient India, Jour. Econ. Social History, of the Orient, 5 (pt. 2, 197): 195-211.
Bailey, K. C., 1929. The Elder Pliny's Chapters on Chemical Subjects, part 1, Edward Arnold & Co., London, 249p.
Bhagvat, R. N., 1933. Knowledge of the metals in ancient India, Jour Chem. Educ. 10:659-666.
Booth, G., 1700. The historical library of Diodorus the Sicilian in 15 books, etc., London.
Caley, E. R., and J. E C. Richards, 1956. Theophrastus on Stones, Ohio State Univ., Columbus, Ohio, 238p.
Davies, O., 1935. Roman Mines in Europe, Clarendon Press, Oxford, 291P.
Fletcher, R. J., 1985. Geochemical exploration for gold in the Red Sea Hills , Sudan, in Prospecting in Areas of Desert Terrain, Inst. Min. Metall., London, pp. 79-94.
Gaskell, J. L., 1985. Reappraisal of Gebeit gold mine, Northeast Sudan: a case history, in Prospecting in Areas of Desert Terrain, Inst. Min. Metall., London, pp. 49-58.
Healy, J. E, 1978. Mining and Metallurgy in the Greek and Roman world, Thames & Hudson, London, 316p.
Rackham, H., transi., 1969. Natural History, by Pliny, vol. 9, Libri 33-35, Harvard Univ. Press, 421P.
Ray, P. C., 1904 , 1925. History of Hindu Chemistry. 2 vols. Chuckervarty and Chatteriee, Calcutta. Rev. ed. in one vol., as History of Chemistry in Ancient and Medieval India, Indian Chemical Society, Calcutta, 1956.
Ray, P R., 1948. Chemistry in ancient India, Jour Chem. Educ. 25:327-335.
Rickard, T. A., 1932. Man and Metals, 2 vols., McGraw-Hill, New York, 1068p.