Low (silicate impurities form diopside, tremolite, or serpentine veins)
density
2.60–2.85 g/cm³
tectonic setting
Contact metamorphic aureoles and regional orogenic belts
Core Principles & Analysis
Regional or contact metamorphism of limestone or dolostone destroys original sedimentary bedding and fossils, recrystallizing carbonate mud and shells into an interlocking mosaic of equigranular calcite crystals.
Pure limestone protoliths yield snow-white statuary marbles such as Carrara, Parian, Pentelic, and Makrana, whereas clay, iron oxide, or magnesium-silicate impurities mobilize during metamorphism into colored veins and green serpentine bands.
Because calcite has a low refractive index that allows light to penetrate 12 to 38 mm beneath a polished surface before scattering out (subsurface scattering), marble exhibits a translucent, lifelike luster prized in classical sculpture and architecture.