Precious metals have always been of interest to humans, be it for their appearance, their properties or their symbolic and economic value. Gold occurs predominantly as a native metal, often found in alluvial deposits and river sand but also in veins, where it usually occurs in minute amounts interspersed in other minerals, such as quartz or pyrite. This metal does not necessarily require a complex technology to be extracted from its alluvial deposits, indeed it was among the first ones to be exploited worldwide (Eluère 1983; Craddock 1995: 144-148). The earliest gold artefacts known were discovered in the cemetery of Varna, Bulgaria, dated to the fifth millennium BC (Eluère 1989; Morteani and Northover 1995; Gale et al. 2003). Some of the earliest mines known, which also date to the Late Neolithic-
Chalcolithic period and were associated with the exploitation of copper ores, were found in eastern Europe at Rudna Glava, Serbia (Jovanovic 1980; 1982; Craddock 1995: 58-60) and Ai Bunar, Bulgaria (Cernych 1978), and at the slightly later Near Eastern sites of Timna, Israel (Rothenberg 1972; Conrad and Rothenberg Conrad and Rothenberg 1980; Craddock 1995: 64-69) and Feinan, Jordan (Hauptmann 1989; Hauptmann et al. 1992; Craddock 1995: 66, 127). The inception of smelting took place in Europe during this same fifth millennium, with evidence of early copper smelting in south Spain and the Alps (Montero Ruiz 1993; Höppner et al. 2005), and was an essential step forward in the history of metallurgy. It also contemporaneously developed in south-west Asia, with extensive evidence found at Timna and Feinan (Rothenberg 1972; Hauptmann 1989; Hauptmann et al. 1992). Mining skills and methods kept improving from the fifth and fourth millennia BC onwards, with various technological breakthroughs and innovations, such as the introduction of fire setting (Craddock 1992), metal tools – subsequently replacing stone tools such as stone hammers –, ventilation and drainage systems to allow mining at greater depths (Craddock 1995: 47-48, 63-64, 71-81).
There is early evidence for the recovery of native gold from sands in the Nubian desert, dated to at least the fourth millennium BC (Forbes 1954: 580). There is plenty of evidence for the early production and use of gold in Europe; however, the extensive exploitation of its primary ores was not a straight and fast process and was established only over a relatively long period of time. Silver was not exploited as early as gold and the reason for its later exploitation is different. Although it also exists as a native metal – but with an exploitable proportion most probably more limited in ancient times compared to copper and gold (Patterson 1971: 299) – and there is evidence of the early use of silver in its native form, for instance in the Aegean in the Bronze Age (Renfrew 1967), silver mainly occurs in compound form in veins and is often associated with lead, sulphur and other base metals. It was therefore necessary to wait for cupellation to be discovered during the fourth millennium BC (Nriagu 1985) to be able to separate the silver from base metals, especially lead. The earliest cupellation process known in the context of primary silver production was performed at the late fourth millennium BC site of Habuba Kabira in Syria (Kohlmeyer 1994; Pernicka et al. 1998) and a small scale two-step
extraction and of cupellation at various Early Bronze Age sites in Siphnos, with potential mines related to the exploitation of gold (Wagner et al. 1980). In addition, recent excavations have unveiled a large quantity of cupellation remains at the site of Lambrika in south-eastern Attica, dated to the final Neolithic-Early Bronze Age period (Georgakopoulou et al. 2008; Georgakopoulou, pers. comm.). There are, in comparison, only rare early silver finds from the same period discovered in the Levant (Prag 1978; 1986; Philip and Rehren 1996), a region where significant metallurgical knowledge existed at that time. One major issue in the ancient metallurgy of silver is the high probability that the quantity of excavated material only represents a small fraction of the actual amount of silver produced and traded in ancient times (Philip and Rehren 1996) due to extensive recycling.
Smelting techniques spread and developed gradually across Europe through the Bronze Age and the Iron Age, mostly in the context of copper production, changing from a relatively basic non-slagging process – at least no evidence of slag has so far been found – to the then widely known slagging process (Craddock 1995: 144-148), and overall increasing the scale of metal production. This, probably combined to the exhaustion of oxidic ores (Patterson 1971: 311), and the developments of mining techniques, led to the exploitation of a wider range of ore minerals, such as sulphides, from the Early Bronze Age onwards in various parts of the world (Hauptmann et al. 2003; Ixer and Pattrick 2003), although it seems that in specific regions such as the Balkans, these minerals were possibly already smelted in the fifth millennium BC alongside oxides (Ryndina et al. 1999; Gale et al. 2003). Many of the present day sulphide deposits may however have been mostly oxides in Antiquity, making it difficult in most cases to identify the nature of the ore deposits in ancient times (Craddock 1995: 10-11).
Late Bronze Age slag from the smelting of complex ore for its silver content has been found in south-west Spain (Rothenberg and Blanco-Freijeiro 1981; Kassianidou 2003), and argentiferous lead ores, mostly galena, were smelted on a large scale at Laurion during the Classical period, as evidenced by the vast beneficiation complex (Conophagos 1980; Tylecote 1987: 125, 135; Rehren et al. 2002; Rehren 2005). Contemporaneously, during the first millennium BC, gold was extensively recovered from placers (alluvial deposits) and mined from veins in the Celtic world (Northover 1995), a good example being the Celtic gold mines in the region of the Limousin,
civilisation and their King Croesus, famous for his colossal wealth gained from the exploitation of alluvial gold, which was refined to produce the first coinage ever known (Ramage and Craddock 2000) (Fig. 2.2).
Fig. 2.1. Fourth-third century BC crucibles
from Cros-Gallet Nord, France (above) and excavation of a La Tène gold mine at la Fagassière, France (right) (after Cauuet 2004: 43, 77).
Fig. 2.2. Lydian Croeseids from
Sardis,Turkey made of pure gold: two of the earliest coins known (after Ramage and Craddock 2000: 129).
In the particular context of the metallurgy of gold and silver, other techniques such as refining were required (Bayley 1991; Bayley 2001). These methods can be divided into two distinct categories: the first separate the noble metals from the base metals and they include smelting followed by cupellation, and the amalgamation of gold from alluvial deposits with mercury; the second are methods used for parting gold from silver, which can be achieved by cementation with salt (Ramage and Craddock 2000), by using sulphur or antimony sulphide, and from the late Middle
Technical developments in mining and smelting continued throughout Roman times and led to the routine exploitation and use of noble metals during the Middle Ages. In Central Europe, famous argentiferous lead mines, e.g. in the Harz Mountains, the Erzgebirge, Rammelsberg, the Black Forest (Steuer and Zimmermann 1993; Goldenberg et al. 1996) to mention the most important ones, and others in southern Europe (Francovich 1993), were exploited for their silver throughout the medieval and modern periods. Gold ores were mined and smelted in Bohemia, the Alps, the Hohe Tauern Mountains (Günther and Paar 2000; Cech and Walach 2001; Cech 2007), Romania, and Iberia. By the early Renaissance, metallurgical techniques and operations used in gold and silver production were widespread knowledge and applied to various types of ores across Europe, culminating in their codification in various texts (see below).
The situation in Europe in the sixteenth century was erratic on various levels. Politically, the Austrian Empire was divided into many provinces controlled by either feudal or ecclesiastical powers, lowering the influence of the central authority. On religious matters, the Lutheran Reformation was spreading widely, intensifying divergence among European populations. The discovery of the New World, and the trade with Asia, created a fundamental change in many peoples’ mind, opening it up for the vast potential of ‘discovery’, but also deeply upsetting established economic and political realities. Great technological advances took place since the Middle Ages, partly thanks to economic changes, resulting in increasing production, capital investments in industries, and transfer of knowledge between craftsmen. These technological developments were also possible due to a progressive cultural movement that increasingly relied on the power of humans, through experiment and observation, to push forward the limits of knowledge, which led to a related gradual change in the perception of nature. This laid out the foundations for the creation of modern science.
Metallurgy, chemistry and alchemy in the sixteenth century were overlapping fields with blurred boundaries. More precisely, alchemy and chemistry were not separated at that time, but were one arena, which is increasingly suggested to be called ‘chymistry’ to avoid terminological and semantic confusion (Newman and Principe 1998; Martinón-Torres 2005: 36-39; Martinón-Torres and Rehren 2005a).
appropriate in the study of the laboratory of Oberstockstall (see below). Chymists and metallurgists, despite sometimes following very different purposes for their activities, shared common operations and this is frequently acknowledged by historical sources (Szabadváry 1992; Newman 2000; Martinón-Torres 2005: 48-51; Martinón-Torres and Rehren 2005a). Among their common activity, fire assay in particular played a crucial part in the development of both disciplines.