Mesopotamian Metals and Minerals

[Note: This article is a preliminary data gathering phase; more work needs to be done to match with Soma purification processes described in the Rigveda, which prima facie seem to match the ancient Mesopotamian texts and ancient Egyptian/Greek texts related to metallurgy of electrum/gold/silver/lead/ copper.]

Partly excavated burial of a lady-in-waiting to a Sumerian royal family of 2500 B.C. was moved intac from Ur to the University Museum of Pennsylvania. Amid the rich ornaments of gold may be seen the teeth of their wearer. From: Samuel Noah Kramer, 1957, The Sumerians in: Old World Archaeology, Readings from Scientific American, San Francisco, WH Freeman and Co.

The tiara from Kunal has eight petals and is reminiscent of the tiara in Pu-abi's grave in Ur. A similar eight-petalled tiara adorrns the 'ram in the thicket' made of gold plate, also found in Ur, Mesopotamia.

The Mesopotamian chronology is as given by J.A. Brinkman in A. Leo Oppenheim, Ancient Mesopotamia (rev. edn., Chicago, 1977, 355ff.):

Products imported into Ur from Dilmun

Products imported into Ur from Magan

Products imported into Ur from Meluhha

Late third and early second millennium BC

Late third millennium BC

Mid-third to mid-second millennium BC

lapis lazuli

cornelian

semi-precious stones

ivory and ivory objects

copper

silver

'fish-eyes'

red gold

white corals

various woods

dates

[Except for the dates and 'fish-eyes', all the commodities came to Dilmun from elsewhere for onward shipment; cf. Tilmun: Edzard et al., 1977, p. 157-8; Groneberg, 1980: 237).

Timber and wooden objects

a type of onion (?)

copper

ivory

gold dust

cornelian

semi-precious stones

diorite

red ochre

goats

[Cornelian and ivory were being shipped from further east; copper and diorite were local].

Akkadian kings claimed to have campaigned in Magan and taken boody. (Potts, D., 1986).

timber and wooden furniture

copper

gold dust

lapis lazuli

cornelian

birds (including peacock)

multi-coloured ivory birds

cornelian monkey

red dog

(Ratnagar, 1981: 66ff.)

Texts refer to it as the land of seafarers.

(P.R.S. Moorey, 1994, Ancient Mesopotamian Materials and Industries, Oxford, Clarendon Press.)

Purification of electrum:
ancient metallurgical processes related to gold, silver, lead

Pliny described electrum as an alloy of gold and silver with one part of silver to four of gold. Normally, in mineralogy, argentiferous gold containing 20-25 per cent of silver is referred to as electrum. "Many of the rare analyses of Mesopotamian 'gold' show that it is in fact electrum, but whether a natural or a deliberate alloy is not invariably clear... Silver may only be separated from gold by a complicated process; but base metals may be slagged off by repeated meltings of native gold in an oxidizing atmosphere, routine in many goldsmithing techniques. Natural electrum can have a susbtantial copper content... Gold, whose distribution is almost universal, occurs either in veins of quartz rock (reef gold) or in alluvial sands and gravel (placer gold); a distinction found in the textual sources (hura_s.um s'a abnisu; hura_s.um s'a ma'e_s'u)... In its native state gold is always alloyed with silver in proportions that vary greatly; sometimes also with copper and traces of iron and other metals... Reef gold occurs as irregular masses in quartz veins or lodes. The mining process consists first of freeing the gold particles by crushing and sifting the ore, then of separating the gold by making use of the metal's higher density. The classic description of gold-mining in antiquity is that by Agatharcides, preserved by Diodorus Siculs (iii.12-14) who, in the second century BC, visited and graphically described the rigours of gold-mining in Egypt (cf. Lucas 1962: 224ff.)... (Royal cemetery at Ur)... a spearhead (U.9122) has 30.30 per cent gold, 59.37 per cent silver, and 10.35 per cent copper (Woolley 1934: 294: table III). The famous rein-ring from RT 800 (Pu-abi) has an equid of electrum (whether natural or artificial is an open question), comprising 65.60 per cent gold, 31.45 per cent silver, and 2.65 per cent copper, whilst the ring on which it stands is virtually sterling silver (93.5 per cent silver, 6.10 per cent coper, and 0.08 per cent gold). Bowls from PG 755 are also gold-silver-copper alloys (Woolley 1934: 294)... Cupellation will remove metals from silver or gold, but by itself will not remove silver; adding salt enables silver to be removed from gold (cementation)...

For cupellation, the gold is alloyed with lead in a special clay vessel, known as a cupel, and the product oxidized by a strong current of air blown into the surface of the molten metal. The base metals are consumed, or drossed, as the oxides formed are absorbed by the porous walls of the cupel, whilst gold and silver survive. Precisely what form cementation took before the classical authors offer descriptions of it (Diodorus Siculus, III.xiv.1f. (after Agatharcides); Strabo, III.ii.8) is a matter of continuing debate. Notton (Notton, JHF, 1974, Ancient Egyptian Gold Refining: a reproduction of early techniques, Gold Bulletin, 7(2), 50 ff.) experimented with the method described by Diodorus Siculus and it proved very successful. A series of tests were conducted in a nine-carat alloy (in the absence of a suitable gold ore). In the first, salt and the gold alloy were smelted under various circumstances. After five days heating at 800deg. C, gold recovery was high. It was less so when salt, brick dust, and the alloy were used and also when tin and lead were added in two different ways. The presence of tin to a greater extent, lead to a lesser, inhibited the recovery rate. On the evidence of these experiments, earlier suggestions about ancient methods of cementation gain extra credence. The Sardis excavators argued that 'the gold is hammered into thin sheets, which are then stacked in a vessel with layers of dry 'pickling mixture' like common salt or alum, and heated for a long time, c. 700 deg. C. Silver especially combines with salts and the gold is left pure (Ramage A. 1970, 'Pactolus North' in GMA Hanfmann and JC Waldbaum, 'The Eleventh and Twelfth Campaigns at Sardis' (1968,1969), Bulletin of American Schools of Oriental Research (Jerusalem and Baghdad) 199: 22-3) . Comparable techniques may have been current in Mesopotamia by at least the Old Babylonian period, to judge from the appearance in the Mari texts of the term lurpianu (a salt?), which is associated with the preparation of gold in contexts suggesting cupellation or a comparable process (Limet.H., 1986, Textes administratifs relatifs aux metaux (Archives Royales de Mari 25, Paris): 288)... The role of assaying in ancient Mesopotamia, in which a sample is removed for analysis, is no clearer. Assay by fire, used in a qualitiative not a quantitiave way, is described in the Leyden Papyrus (X, no. 3: Oddy, W.A., 1983, Assaying in Antiquity, Gold Bulletin, 16(2), 52-9), but how early such tests were used is unknown: 'If the gold is pure, it keeps the same colour and remains pure like coinage after heating. If it appears whiter it contains silver; if rougher and harder, it contains copper and tin; if black and soft, it contains lead.' The use of a touchstone (Lapis Lydius, i.e. black chert) to test the relative purity of gold (its approximate carat value in modern terms) is attested by classical authors from at least the sixth century BC (Theognis, 417; Pindar, Pythian, X.67). Theophrastus (de Lapidus, 45) attributes them to the river Tmolus in TUrkey. In this case it is siliceous schist (flinty state), black in colour, usually for this purpose deep black, fine-grained; but other black stones may be used.. Streaks are taken from gold alloys of known, graded composition for comparison with streaks taken from the metal to be assayed (cf. Oddy 1983; Moore and Oddy 1985)... Eluere (1986: 59) has shown that two stones from a late third-millennium grave at Telloh (called a 'goldsmith's tomb') exhibit no traces of gold and are not suitable for use as touchstones; the same is likely to be true of an example identified at Larsa in a 'jeweller's hoard' (cf. Arnaud et al. 1979: 20-1, 23, fig.8). These haematite objects are either weights or burnishing stones, as may be the case with a gold-streaked stone reported from Assur (Pedersen 1985: 123, n.7); this type of stone is not appropriate for use in a touchstone...

Sumerian literary texts refer to gold from Aratta (Pettinato 1972: 79). Gudea records receiving gold from the mountain of Hah(h)um (Statue B. col. VI. 33-5; Liverani 1988), taken to lie in that part of modern Turkey near Samsat on the Upper Euphrates, and from Meluhha. In far less explicit terms the names of various mountains reputed to have gold sources are also recorded (Limet 1960: 94). Various texts refer to the almost mythical land of gold known as (H)arallu, perhaps somewhere in the Iranian hinterland (Komoroczy 1972; Groneberg 1980: 20). Shu-Sin (c. 2037-29 BC) refers to gold from 'Su-land', probably in western Iran, though its location is still open (Edzard, D.O., 1959-60, Neuen Inschriften zur Geschichte von Ur III unter S'usuen, Archiv fur Orientforschung (Graz) 19, 1-32): 16-18) and from (Mar)daman, possibly identical with Mardin in south-east Turkey (ibid.: 7; Edzard and Farber 1974: 118). Documents relevant to the Dilmun, trade in the later third and earlier second millennium BC indicate that some gold was still reaching Ur up the Gulf at this time, but whence it came, perhaps Meluhha, is not stated (Oppenheim, A.L., 1954, The Seafaring Merchants of Ur, Journal of the American Oriental Society (New Haven, Conn.) 74, 6-17: 7; Leemans, W.F. 1960, Foreign Trade in the Old Babylonian Period as revealed by texts from southern Mesopotamia (Leiden): 120-1, is more cautious; cf. Leemans, W.F., 1957-71, Gold, Reallexikon der Assyriologie und vorderasiatischen Archaologie (Berlin) 3, 504-31). The renowned resources of Egypt and Nubia (cf. Lucas 1962: 224-8) contributed most certainly in the fourteenth century BC to Mesopotamian royal gold holdings (Edzard 1960; Wilhelm 174). Then, for the first and only time in its history, Babylonia may have adopted the gold standard and large amounts of gold came from Egypt to assist Kurigalzu I in his major building projects (Brinkman 1972: 274-5; Muller 1982; Powell 1990: 79-82). Hittite inventory texts of the thirteenth century BC record gold from Babylon and Lukka (Lycia) (Kosak 1982: 195)...

So far as is known, there were no sources of gold exploited in antiquity in Mesopotamia, Syria, or Palestine; but the metal is widely reported on the periphery of this region (Maxwell-Hyslop 1977): in Turkey, where there is a preponderance of sources in the west and south-west (Jesus 1980: 82 ff.); in Egypt and Nubia (Lucas 1962: 224-8); in considerable quantities in western and southen Arabia, not least in Ophir (I Chron. 29: 4; 1 Kgs. 10; Job 22: 24; cf. Maisler 1951), being well known to both biblical and classical auhors (Diodorus Siculus, III, xlv. 6 ff.; Strabo, xvi. 4,18,22: Periplus, 36, etc.); in greater Iran, notably in the north of the country and eastwards into Transoxiana and the region of modern Afghanistan, where there are substantial vein and placer deposits (Dunlop 1957; Chmyriov et al. 1973). Diodorus Siculus (II.xxxvi.2) and Pliny (Natural History, xxiii.66) refer to rich soures in India, though traces are no longer easy to detect (Allchin 1962; Ratnagar 1981: 106 ff.) With so wide a range of potential sources within her orbit, many of them in regions whence she is known to have received other metals. Mesopotamia is likely to have had a variety of choices if and when supplies were for some reason blocked in any particular locality. It will be immediately clear that the ancient texts already considered indicate import at various times from all the potential sources zones listed here.

The wide distribution of potential sources does not ease the quest for a scientific method through which Mesopotamian gold sources might be 'finger printed'. It is known that platinum group elements (hereinafter called PGE) such as ruthenium, rhodium, palladium, osmium, iridium, and platinum occur in gold objects from the ancient Near East both in solid solution and as inclusions.. On the evidence of the inclusions of the platiniridium alloy in a number of Sumerian and other ancient gold objects, notably Lydian gold coins supposedly of gold from the Pactolus valley in western Turkey, Young (W.J. 1972; cf. Whitmore and Young 1973) argued that this region has been an important source of Sumerian gold. Within a few years Ogden (1977), after a comprehensive review, concluded that direct correlation of a gold object and its metal source through the PGE inclusions was not feasible. Maxwell-Hyslop (1977) also questioned the Whitmore and Young hypothesis, pointed to other more likely and closer sources for Sumerian gold, both in eastern Turkey and in Iran... The gross distinction seems to be that the Sumerians drew upon sources of gold other than those most easily accessible to western regions...

Silver... Silver is found in nature both as a metal and in its non-metallic state. It also occurs in practically all gold. Native silver is rare (20 per cent is abundant as gold; 0.2 per cent as abundant as native copper) and is usually found in quantities not worth melting to make larger, workable lumps (Patterson 1971)... The principal ores of silver are the sulphides (argentite: silver glance) and the chlorides (cerargyrite: horn silver), which yielded up their metal by simple smelting. It has long been generally assumed that most of the silver used in the Near East in antiquity was extracted from argentiferous lead ores, notably galena (lead sulphide) and cerussite (lead carbonate)...it appears, Aegean silver was largely produced from galena.

Two steps are involved in producing silver from lead ores. Lead ore is melted first under the appropriate reducing and/or oxidizing conditions to produce metallic lead. Silver is then extracted from the lead by cupellation by which the lead is oxidised to litharge (lead oxide), leaving behind the silver. For this the lead is heated under strongly oxidizing conditions in a cupel. The lead oxide so formed is absorbed in the porous material of bone or ground-up potsherds in the cupel, leaving silver metal behind. This process may be repeated several times to purify the silver; it is very efficient in freeing silver from such common impurities as copper, antimony, arsenic, tin, iron, zinc (less well for bismuth), in the argentiferous lead. Silver derived from argentiferous galena will be characterized by gold contents from zero to about 0.5 per cent, lead contents between 0.01 per cent and 1 per cent, or rarely a little higher (Gale and Stos-Gale 1981: 107). Silver derived from the native metal, with or without admixture of cerargyrite (a 'dry silver' ore very easily reduced to silver metal), will generally contain less than 0.01 per cent gold and significant quantities of mercury (ibid.). It is possible that silver was recovered sometimes from the cementation process through which electrum was purified into gold. But there is, as yet, no hard evidence for this from literary, archaeological, or analytical sources, in the area and time range considered here.

It has recently been suggested that liquation, using lead metal to extract silver from copper, thought first to have been described by Agricola in the Ranaissance, had already been practised in the Late Bronze Age in installations excavated at Ras Ibn Hani in Syria (Bordreuil et al. 1984: 404-8, figs. 4-5). This identification is doubtful. The Old Babylonian texts from Mari cited in support of the existence of this process in the Near East in the second millennium BC do not sustain the case. They indicate that 'mountain copper' was 'washed' (?purified/refined) to produce 'washed copper' and that lead was used with silver toproduce 'washed silver'; but they do not show that lead was added to copper to produce 'washed silver'; but they do not show that lead was added to copper to produce 'washed' silver, which is what would be expected if they are to be taken as evidence for the extraction of silver from coper by liquation (Bordreuil et al 1984: 407l citing Durand). That lead was plentiful in excavations at Ras Ibn Hani is not relevant to this question. What matters it the method of purifying, and there is no reason to suppose it was liquation either at Mari or at Ras Ibn Hani (cf. Muhly, J.D., 1988, The wider world of lead ingots, Report of the Department of Antiquities (Cyprus, Nicosia) 263-5).

Any conjectures about the origins of silver metallurgy in the Near East have to take into account the long interval between the first appearance of lead, some time in the seventh millennium BC in Turkey (Jesus 1980: 76), and the earliest manufactured silver, some three millennia later, when it appears relatively suddenly over a wide area (Prag 1978). Lead, which could only have been obtained by smelting, had long been experimented with before the appearance of silver. The view, argued over a longg period by a number of scholas (cf. Gowland 1920: 132; Hoover 1950: 390; Wertime 1973: 883), that silver was discovered in the course of the accidental cupellation of lead, remains a strong possibility in the Near East. But, even after the initial discovery, the recovery of worthwhile quantities of silver required the solution of a number of technical difficulties, for a tone of smelted lead will only contain a few ounces of silver.

Oppenheim (1966) published and commented on a text from the library of Ashurbanipal (668-627 BC), for making a silver-like alloy from base-metal ingredients. How much older such deceptions were has yet to be established. The later economic texts from Mesopotamia are much concerned with the quality of silver and carefully stress the percentage of permitted additions; but far too few analyses have been done to offer any information on the ways in which, for specific purposes, silver might be debased. Nor, owing to the way in which buried silver corrodes, is it likely that archaeology will ever peovide any check on textual indications that silver surfaces were variously treated with heat (Limet 1960: 49-50). Moreover under field conditions corroded silver may easily be confused with copper or bronze, so the number of silver objects from excavations may at present be underrated.

As Limet (1960: 94) has pointed out, textual indications for the ultimate sources of the silver used in Mesopotamia are singularly rare and meagre. Pettinato (1972: 80-1), in his review of the Sumerian literary evidence, listed such relatively well-known regions in Iran, the Gulf and the Indus valley, as Aratta, Dilmun, Elam, Marhashi, and Meluhha. 'The Silver Mountains' limited the campaigns of Sargon of Akkad to the north-west (Hirsch 1963: 38, lines 22-8) and are usually identified with silver-mines at Keban on the Upper Euphrates, just south of its junction with the Murat river. Manishtushu recorded a campaign in which his army was divided into two, one part invaded 'Anshan and Sherikhum' in Iran, whilst the other waged war 'up to the silver mines' (Hirsch 1963: 69; Gadd 1971: 438 ff. considers the geographical problems). Heimpel (1982: 67) suggests they might just be 'metal mines'. Gudea wrote of silver from its mountain, taken by Limet (1960: 94-5) to refer to a source east of the Tigris in Iran. In his summary table of the evidence provided by the lips'ur litanies and the HAR-ra series 22, Snell (1982: 212) lists Zar-s'u, Has'bar, la-an-na-ki-ta, and Ku-su as silver sources; but of these places only one may be tentatively identified: Ku-su? = Kush (Nubia) and that seems unlikely before the first millennium BC. It is to the earlier second millennium BC that some of the best textual evidence for the use of Anatolian silver belongs Larsen (1967: 4) has succinctly described the famous trade between Assur and eastern Anatolia at this time: 'The pattern of the trade as revealed by the texts is clear; tin and textiles were imported into Anatolia and n return silver and gold were sent back to Assyria. The trade in copper was vigorous but seems to have been mainly an internal Anatolian affair.' The silver was either in ingots passing by weight, or sometimes in rings or packages containing bars of metal. Different types of silver are distinguished, probably by quality; various towns in the vicinity of Kultepe (karum Kanesh) are listed as the sources of silver, but they are probably just the principal centres for its distribution (Garelli 1963: 265ff.). Leemans (1960: 130 ff.) preferred not to speculate on the origin of the silver current in Babylonia during the Old Babylonian period, as it was then widely used as currency. There is some indication of silver coming up the Gulf (Oppenheim 1954). Hittite inventory texts of the thirteenth century BC attribute silver to Saqqamaha and Arpa in the north-central region of Turkey (Kos'ak 1982: 197)... Shalmaneser III wrote of going to 'Mount Tunni (Taurus), the silver mountain, (and) Mount Muli, the marble mountain' (Meissner 1912; Luckenbill 1926-7; i.246). According to the 'Foundation Charter' of Darius I, the silver used in his time at Susa was from Egypt (Vallat 1971)...

Marco Polo documents productive silver mines in Badakhshan (i.24; cf. Chmyriov et al 1973)... Modern mineralogical reports on Afghanistan suggest the sources lay outside this modern political unit, since it is said to have virtually no silver and its numerous lead deposits are very low in silver (Stech and Pigott 198y: 49). India is a possible silver source according to classical sources (Strabo, xv.i.30, cap. 700; Ktesias, Indika, cap. II), though Ratnagar (1981: 140ff.) attributes the rare occurrences of silver in the Indus Valley Civilization to trade with Sumer...

Copper... Muhly (1973: 220ff.; 1976: 104 ff.) has thoroughly reviewed the ancient textual sources for the use of copper and its trade in Mesopotamia, with extensive commentary on their relation to known deposits in the area. Archaic texts from Uruk (III) indicate that already by the later fourth millennium BC Dilmun was engaged in the metals trade (Englund 1983). In the third millennium Sumerian texts list copper among the raw materials reaching Uruk from Aratta (Pettinato 1972: 82-3, 128) and all three of the regions Magan, Meluhha and Dilmun are associated with copper, but the latter only as an emporium (Limet 1960: 85ff.; Waetzoldt 1981). Gudea refers obliquely to receiving copper from Dilmun: 'He (Gudea) conferred with the divine Ninzaga ( = Enzak of Dilmun), who transported copper like grain deliveries to the temple builder Gudea...' (Cylinder A. XV. 11-18: Englund 1983: 88, n.6). Magan was certainly a land producing the metal, since it is occasionally referred to as the 'mountain of copper'. It may also have been the source of finished bronze objects (Limet 1972: 1417).

In the early second millennium BC Mesopotamia may have lost direct contact with Magan, and with Meluhha, also earlier mentioned in relation to copper. Copper now came through Dilmun and its traders. Gudea refers to mining copper in the mountain of Kimas' (Falkenstein 1966: i.50 ff.; Statue B.VI: 21-3). This region is assumed to have been somewhere between the Jebel Hamrin and the Lesser Zab (Edzard and Farber 1974: 100-1); an old identification with Ergani Maden in Anatolia is no longer regarded as tenable. If this location is correct, it may have been just an entrepot for copper from mines deep in Iran, or it might be a direct reference to the copper-mines visited by Layard in the Tiyari mountains, north of Amadiyeh (Layard 1849: i.223)... Anatolia was not an exporter of copper in the third and early second millennium BC... As already noticed, after the Ur III period direct trade from Mesopotamia down the Gulf to Magan appears to stop and Dilmun becomes the primary entrepot for all Gulf Trade, including metals, in the earlier second millennium BC. Copper came this way until at least the eighteenth century BC, when there is a break in the records almost exactly at the same time as the earliest surviving textual indications of copper from Alashiya (Cyprus) reaching Mari and Babylonia (CAD. alas'u; Schaeffer 1971: 547 ff.; Millard 1973). The Mari texts also refer to a type of copper qualified by the term te-ma-yu, for which Dossin (1970a: 39 n.1) suggested an association with Teima in Saudi Arabia, serving as an entrepot for copper from the Feinan/Wadi Arabah mines (cf. Hauptmann et al 1989). Muhly (1976: 109) was sceptical; but it is not an impossibel routing.

It has been argued that it was the eclipse of the Indus Valley civilization in the second millennium BC that brought to an end the flourishing Indus-Mesopotamian trade up the Gulf; but this has yet to be satisfactorily confirmed. Stray indicators suggest continuing, if intermittent activity. In the middle of the fourht century BC a Babylonian official was stationed on Dilmun, whence he reported back on local threats to the date crop. Then Tukulti-Ninurta I of Assyria (c. 1243-1207 BC), after his sack of Babylon, assumed the title 'King of Dilmun and Meluhha', emphasizing contemporary Babylonian interest in these regions, even if the full implications of the ancient names no longer applied (Brinkman 1972: 275-6; 1976: 314)...(Moorey, 1994, p. 217ff.)

Ur, Dummy head with jewellery from an attendant in the Great Death Pit	Ur, Ram in the thicket, UPenn Museum
Kunal: Silver ornaments, spiralled silver bangles
Discular beads of gold with axial perforation, Mature Harappan, Lothal
Discular beads of silver with axial perforation, Early Harappan, Kunal

Quartz containing gold ore	Pellets of gold ore (which look like plant stems)
Mortar and pestle used to crush the quartz	.Molten gold being poured from a crucible into a vessel
Pouring molten gold from a crucible into a mould	Gold nuggets
Touchstone to test the quality of gold

Ubaid	c. 5500-4000 BC
Uruk (Early/Middle)	c. 4000-3500 BC
Uruk (Late/Jamdat Nasr)	c. 3500-3000 BC
Early Dynastic I	c. 3000-2750 BC
Early Dynastic II	c. 2750-3600 BC
Early Dynastic III	c. 2600-2350 BC
Akkadian (or Sargonic)	c. 2100-2000 BC
Ur III	c. 2100-2000 BC
Isin-Larsa/Old Babylonian/Old Assyrian	c. 2000-1600 BC
Kassite/Mitannian/Middle Babylonian/Middle Assyrian	c. 1600-1000 BC