Black Marble
Recrystallized Carbonate Rock (CaCO3)
Rock Type: metamorphic

Physical Properties
Hardness: 3-4 on Mohs scale; Color: Black to dark grey with white calcite veining; Luster: Polished/Vitreous; Crystal Structure: Trigonal (microcrystalline); Cleavage: Perfect rhombohedral (but generally massive)
Formation & Geological History
Formed from the regional metamorphism of limestone or dolostone. High pressure and temperature cause the calcite crystals to recrystallize into a dense interlocking mosaic. The black color usually comes from carbonaceous material or bitumen trapped during formation.
Uses & Applications
Used extensively in interior decoration, flooring, sculptures, tabletops, and metaphysical items like polished spheres or massage tools.
Geological Facts
Marble has been used since antiquity in Roman and Greek architecture. The veins found in black marble are structural cracks filled with secondary minerals, usually white calcite, creating the 'lightning' effect seen here.
Field Identification & Locations
Identify by its softness (can be scratched by a steel blade) and its effervescence when in contact with dilute hydrochloric acid. Commonly found in regions with ancient mountain building activity like Italy, Spain, and China.
Identified on: 5/16/2026
Mode: Standard