Stone or rock is one of the oldest materials used to make sculptures. Due to its hardness, it is very durable. Freshly cut or quarried stone is best suited for carving, as exposed stone will have formed a hard, weathered skin. Sculptors extensively study different types of stone and their specific qualities and characteristics. There are three basic rock formations: igneous rock, metamorphic rock and sedimentary rock. Igneous rock, such as basalt or granite, is formed by cooled magma from the molten interior of the earth. Metamorphic rock such as slate and marble is very hard and resistant to weathering because during natural formation it is subjected to extreme heat and / or pressure. Sedimentary rock which includes limestone and sandstone, is formed by successive layers of deposits that have settled at the bottom of a lake, sea or ocean. Limestone is one of the most widely used because it is easy to carve and can be very finely polished. Prior to carving a sculptor checks the stone for any imperfections, and sets it up in a fixed position, and in accordance with the bed it has come from. The bed is the way the stone was positioned in the quarry, with horizontal layers. If the stone is not set up correctly it will split when carved. The cutting and carving, is done by hitting a hardened steel tool into the stone with a mallet, a type of hammer made in wood or metal. The main tools for carving are the point, the claw, and the chisel, which come in different shapes and sizes, depending on the type of stone used. A point is used to cut or chip larger bits of stone away. To get closer to the desired shape, a claw is used, creating a cross-hatched surface. To create finer detail, and to smoothen the surface of the finalised piece, a chisel and diamond abrasive tools are used.

 

image: Egypt (664-525BC) Scarab, (H1148)