Marble

Physical Properties

Hardness: 3 on Mohs scale; Color: White with grey veining; Luster: Subvitreous to pearly; Crystal structure: Trigonal/Rhombohedral; Cleavage: Perfect rhombohedral (in mineral form); Specific gravity: 2.7

Formation & Geological History

Formed when limestone is subjected to the heat and pressure of metamorphism. It is composed primarily of the mineral calcite. Formation occurs over millions of years along convergent plate boundaries.

Uses & Applications

Extensively used for luxury countertops, flooring, flooring tiles, architectural sculpture, and as a calcium supplement in livestock feed.

Geological Facts

Pure white marble is the result of metamorphism of very pure limestone. The characteristic swirls and veins of many colored marble varieties are usually due to various mineral impurities such as clay, silt, sand, or iron oxides.

Field Identification & Locations

Identify by its softness (can be scratched by a metal blade) and its reaction to dilute acid (it will effervesce). Common in Italy (Carrara), Greece, and Vermont.

Identified on: 4/16/2026

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