Aragonite Star Cluster

Physical Properties

Hardness: 3.5-4.0; Color: Reddish-brown, orange, or honey-colored; Luster: Vitreous to resinous; Crystal structure: Orthorhombic (twinned pseudo-hexagonal prisms); Cleavage: Distinct in one direction; Specific Gravity: 2.95

Formation & Geological History

Formed at low temperatures near the Earth's surface through precipitation in sedimentary environments or hydrothermal veins. These specific 'Sputnik' clusters are often found in gypsum clays or marls.

Uses & Applications

Primarily used as decorative display specimens for collectors and in metaphysical practices. Industrial aragonite is used as a soil conditioner and in the manufacture of glass and cement.

Geological Facts

Aragonite is a polymorph of calcium carbonate, meaning it has the same chemical formula as calcite but a different crystal structure. Over long geological periods, aragonite naturally reverts to the more stable calcite.

Field Identification & Locations

Identified by its radiation of hexagonal-shaped prisms from a central point. It will effervesce (fizz) vigorously when in contact with weak hydrochloric acid. Commonly found in Morocco (Tazouta), Spain (Aragon), and Mexico.

Identified on: 4/13/2026

Mode: Standard