An Introduction to Marbles

Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite. Marble may be foliated. In geology the term “marble” refers to metamorphosed limestone, but its use in stone masonry more broadly encompasses unmetamorphosed limestone. Marble is commonly used for sculpture and as a building material.

The word “marble” derives from the Ancient Greek μάρμαρον (mármaron), from μάρμαρος (mármaros), “crystalline rock, shining stone”, perhaps from the verb μαρμαίρω (marmaírō), “to flash, sparkle, gleam”; R. S. P. Beekes has suggested that a “Pre-Greek origin is probable.”

This stem is also the basis for the English word marmoreal, meaning “marble-like.” While the English term resembles the French marbre, most other European languages follow the original Greek.

Physical origins
Marble is a rock resulting from metamorphism of sedimentary carbonate rocks, most commonly limestone or dolomite rock. Metamorphism causes variable re crystallization of the original carbonate mineral grains. The resulting marble rock is typically composed of an interlocking mosaic of carbonate crystals. Primary sedimentary textures and structures of the original carbonate rock (protolith) have typically been modified or destroyed.

Pure white marble is the result of metamorphism of a very pure (silicate-poor) limestone or dolomite protolith. The characteristic swirls and veins of many colored marble varieties are usually due to various mineral impurities such as clay, silt, sand, iron oxides, or chert which were originally present as grains or layers in the limestone. Green coloration is often due to serpentine resulting from originally magnesium-rich limestone or dolostone with silica impurities. These various impurities have been mobilized and recrystallized by the intense pressure and heat of the metamorphism.