The State Hermitage Museum: Exhibitions

Working stone (from the archives)

The initial processing of stones consists of rough-hewing them with steel tools: cutting up the stone, which is done with plates of sheet iron. Sometimes, especially in the case of round items, the round shape is drilled using a pipe or cylinder of sheet iron driven by a machine. The cavities in round items are also drilled out using such tubes. Abrasive and water are frequently applied to both the saws and the drill bits.

After a stone has thus been given its first rough appearance, it is gradually brought to its true shape, first on a machine where it is pressed by screws onto rotating wooden wheels that are also constantly moistened with abrasive and water.

If an item is round, then the stone is then attached at the centre and made to rotate, being gradually given its final form by wooden, then iron rasps or grindstones. Items of various rounded shapes, oval, flat, angular and so on, are processed for the most part using cams called rockers, then finished by hand.

When all parts of the piece match the template, they begin grinding and polishing. The former is also done with abrasive, but of a finer sort than before. Then, right before polishing, the entire piece is ground with the finest abrasive. Polishing is performed by tin rasps and wheels with a fine tooth. Round items are polished while rotating. Flat and other shaped items are ground and polished by hand.

For pieces that are to be carved in the form of a bas-relief, a wax model is first made from the design, then the figures are drawn onto the stone with a copper stylus. They are marked out with a fine chisel and after that figures are worked using machines. In this case too the figure is ground and polished by hand as described above.

Besides the pieces made of whole hard stone, the works also produces composite pieces in malachite and lapis lazuli. For this they first prepare a piece of a particular shape from serpentine, marble or some other hard stone proceeding from the size and purpose of the item. Meanwhile plates [of the mineral] are prepared two or three lines (5–7.5 mm) thick. The malachite or lapis lazuli is sliced using thin sheet iron and finely powdered abrasive. When the form and a sufficient quantity of plates have been prepared, the latter are applied to the former using tin. Each plate is made to fit the next with the finest abrasive using small lead wheels. In doing so, they look to ensure that the patterns and colour of the plates correspond as much as is required. A special mastic incorporating malachite powder is used to fix malachite. Lapis lazuli is ground and polished in exactly the same way as other stones. For shaping and grinding malachite, the abrasive is replaced by whetstone and “English stone”. The former is nothing other than fine-grain sandstone, the latter a type of fine slaty shale. The polishing of malachite also differs from that of hard stone. It is polished first with finely powdered bone ash, then with a powder made from tin scalded with aqua fortis to which a small amount of sulphur is added. Depending on their shape, mosaic items are also processed by rotation or simply by hand.