The famous Rosetta Stone was carved from basalt.
Basalt is the most plentiful rock in the earth’s crust. Though the continental land masses are mostly granite, the vast ocean floors are mainly basalt. It’s an extrusive igneous rock formed when volcanic magma erupts onto the surface or into water and cools quickly. The speed of the cooling process makes mineral formation in basalt almost invisible and its composition fine-grained and consistent. Basalt in any form has no toxic properties and is noncombustible and nonexplosive.
Basalt is most commonly used as an aggregate for construction. Crushed or powdered basalt is blended into concrete as a filler to add strength. It is also mixed into road paving materials like asphalt. Rugged tiles can be produced from basalt; most of the roads and walkways of ancient Rome were paved with them. The large quantity of coarse, crushed rock that makes up the ballast along railroad tracks is frequently basalt, too.
Basalt has excellent insulating properties. Its thermal protection exceeds that of other natural substances. It has three times the heat insulation value of asbestos with none of its toxic hazards. Basalt’s favorable friction characteristics have made it an excellent replacement for asbestos in automotive applications such as brake linings. Unlike carbon fiber, basalt is electrically nonconductive and can be used as an electrical insulator.
The tensile strength of basalt exceeds Fiberglas and carbon fiber and is just slightly less than carbon steel. When melted and extruded into fine fibers, composites made of basalt are used to produce pipe, construction rebar and even the enormous blades of wind power turbines.
Sculpture And Ancient Artifacts
Since antiquity, basalt’s widespread occurrence, homogenous gray color, and fine-grained hardness has attracted sculptors. Half of the massive Moai icons on Easter Island are carved of basalt. So is the famous Rosetta Stone, used to decipher Egyptian hieroglyphics. Basalt busts and statues populate the Greek and Roman empires, and many carved artifacts of those eras, from jewelry and vases to graceful columns, were hewn from basalt.