Marble

Physical Properties

Hardness: 3 on Mohs scale. Color: White with grey and peach/reddish veining. Luster: Vitreous to waxy. Crystal Structure: Trigonal (granular). Cleavage: Perfect rhombohedral in individual crystals. Specific gravity: 2.7.

Formation & Geological History

Formed through the regional or contact metamorphism of sedimentary limestone or dolostone. Under extreme heat and pressure, the calcite crystals recrystallize into a dense interlocking mosaic. This specimen shows 'water-worn' smoothing, likely from a river or beach environment.

Uses & Applications

Used in sculpture, construction (countertops and floor tiles), as an industrial crushed stone, and occasionally tumbled for pocket stones or decorative gravel.

Geological Facts

The colors in marble, like the grey and reddish-orange streaks seen here, are caused by mineral impurities such as clay, silt, sand, or iron oxides that were present in the original limestone.

Field Identification & Locations

Identify in the field by its softness (can be scratched by a steel knife) and its reaction to dilute hydrochloric acid (it will fizz/effervesce). These smooth, pebble-like specimens are common in areas where metamorphic bedrock has been eroded by water.

Identified on: 4/20/2026

Mode: Standard