Dr Robert Sturm (Austria)
This is the third of four articles on the quarries of the ancient world and later, and, in particular, the marble that was quarried there and the works of art made from it. The first is Mining in Ancient Greece and Rome and the second is Marble from the Isle of Paros – a tour of the ancient quarries.
The ancient methods used
An antique quarry is interesting because it is a place where raw material for buildings and sculptural works was extracted to specific sizes and shapes with the technical methods of that time. The mining techniques did not change very much from the earliest phases of human civilization until the end of antiquity, even though the methods used continuously improved over time. In ancient Greece, single blocks of the stone were separated by smashing several key holes into the rock wall, into which wooden wedges were driven. After that, the wedges were moistened, causing their expansion and the cracking of the block along the line of holes. For a better control of the rock fracture, long groves were carved into the blocks with iron tools, into which key holes were subsequently inserted. Alternatively, the blocks were completely split off from the rock walls by deep cuts in the rock and then separated from the ground using crowbars (Fig. 1).
Since archaic times, rock saws have also been used. In the Roman era, these tools were replaced by so-called ‘pendulum saws’, with single blades measuring 6m in length. The cutting efficiency of the saws was increased by using quartz sand that was suspended in water and flushed into the groove.
Work on the raw material mined in the quarry usually started at the place from which it was extracted. This is indicated by the many semi-finished columns, capitals, obelisks and sculptures that can be found at some of these sites. The most famous example of a half-finished sculpture is the so-called Kouros of Naxos, which is still attached to its block. The main reason for the preliminary work on the rock being carried out in the quarry was the high cost of renting transport, which became much cheaper after the removal of unnecessary rock ballast from the half-finished architectural pieces. Transport of the material away from the quarry was carried out using carts or, in the case of very heavy pieces, on specially produced slides. If the quarry was situated near the sea or in the direct vicinity of a river, transport of the material was preferably conducted along the waterway.
While in ancient Greece, quarries were generally in the possession of the state, in the Roman Republic, they mostly passed into private hands. Under Emperor Augustus, the founder of the Roman Empire, most quarries came back into public or imperial possession and were managed by public servants or leased to entrepreneurs. In the fourth century AD, Emperor Constantius, the father of Constantinus the Great, again tried to denationalise the quarries, but had only very marginal success.
For the heavy work including the separation of giant stone blocks, prisoners of war and slaves were mainly used. Along with these people, free craftsmen and soldiers were also used to extract and work the rocks. The main rock types, which were subject to extensive use in ancient times, included marble, limestone, granite, porphyry and sandstone.
Famous Roman quarries in Austria
1) The lime-sandstone quarry in St Margarethen (Eastern Austria)
The so-called ‘Roman quarry’ of St Margarethen is the oldest active place involved in the extraction of rock in Austria. The limestone/sandstone exposed in this quarry was already used for the building of the famous imperial city of Carnuntum 2,000 years ago. In the sixteenth century, the quarry attained supra-regional significance and came into the possession of the famous landowning Esterházy family. At this time and in the following centuries, the limestone/sandstone was primarily used for cathedrals and numerous buildings built on the great road that circled Vienna. In 2001, the quarry attained ‘World Cultural Heritage’ status due to its immense cultural importance. Nowadays, a 150,000m2 area of the quarry is used as an open-air museum, which is freely accessible to visitors. Fossil finds, which were made in the mine in the past centuries, are exhibited in a small museum. This exhibition hall also contains numerous sculptures made in the past few decades (Fig. 2).
2) The marble quarries in the county of Salzburg
South of the city of Salzburg, two famous marble quarries had already achieved a noticeable significance in Roman times. The first one is the quarry on the northern flank of the ‘Untersberg’, a 1,800m-high mountain about 6km from the city, which is a popular tourist attraction (Fig. 3). Strictly speaking, the marble extracted in this mine is only a bright and pure limestone, and the term ‘marble’ was given to this rock primarily because it was used as a sculptural and decorative material. Furthermore, the stony material can be cut and polished like normal marble. Geologically, the limestone of the ‘Untersberg’ is from the Upper Cretaceous (about 70 Ma), whose colour varies from beige to pink and red and, very rarely, yellow. In addition to its use during the Roman era, the rock has been mined since the early eighteenth century and is in very high demand even today.
The marble quarry of the village of Adnet, 15km south of Salzburg, was used by the Romans in the second and third centuries AD (Fig. 4). The limestone exposed in this mine was used for relief sculptures, buildings and also mosaics, some of which are exhibited in the Salzburg Museum. In the Middle Ages, the rock still enjoyed great popularity and was used for (among other things) sacral sculptures, columns and various other monuments. Numerous gothic masterpieces created by Veit Stoß, Tilman Riemenschneider and Niclaes Gerhaert van Leyden are composed of the limestone from here, which was formed during the Mesozoic period. Small amounts of hematite give the rock its typical red colour. However, if the concentration of limonite is enhanced, the limestone is characterised by a brownish to yellow colour.
Famous Roman quarries in Germany
1) The sandstone quarry of the Kriemhildenstuhl in the Rhenish Palatinate (Central Germany)
This famous sandstone quarry is situated near the city of Bad Dürkheim (Rhenish Palatinate) and was managed by the 22nd legion of the Roman army stationed in Mainz in 200 AD and the following decades. Mining activity was continued until the middle ages. At this time, the rock was mainly used for buildings and walls (Fig. 5).
The semicircular quarry of the Kriemhildenstuhl became famous due to its whitish quartzitic sandstone, whose appearance is reminiscent of a bright marble. Mining of the rock was chiefly carried out near the plateau, because at this place, the sandstone was only covered by a thin layer of earth. The stone blocks hauled in the quarry had a length between 1.2m and 3m, a width ranging from 0.6m to 1.4m, and a height of 0.6m. In certain cases, capitols and rounded blocks intended for columns were also produced. The blocks were transported to the valley on runners and log rolls.
2) The quartz-diorite of the Felsberg in the Odenwald (Central Germany)
The so-called ‘Felsenmeer’ in the German Odenwald represents a large deposit of rounded quartz-diorite blocks formed by so-called ‘wool-sack weathering’. At the base of this deposit, 15 workshops from the Roman era can be found. They contain 300 unfinished or damaged ancient work pieces, which represent the main attractions for tourists from all over the world (Fig. 6).
Some concluding remarks
The duration of the Roman presence in this natural deposit is limited to the second to fourth centuries AD. The ‘Felsenmeer’ is visited by 100,000 people every year, who mainly come to the deposit at the weekends. Today, it represents a so-called Natura 2000 area (that is, a nature protection area in the European Union) as a result of its historical and ecological significance.
Sturm, R.: Cameos from ancient Greece and Rome: small but precious treasures. Deposits Magazine, 34, 44-46 (2013).
Sturm, R.: Tauern gold: the history of gold mining in the Central Alps. Deposits Magazine, 37, 39-40 (2014).
Sturm, R.: Mining in ancient Greece and Rome. Deposits Magazine, 41, 43-45 (2015).
Sturm, R.: Marble from the Isle of Paros – a tour of the ancient quarries. Deposits Magazine, 51, 48-49 (2017).