mineral

Honey calcite (optical calcite)

Calcite, calcium carbonate (CaCO₃)

AI-generated identification · may be incorrect

Transparent to translucent pale honey-colored cleavage specimen with vitreous to pearly luster and prominent rhombohedral cleavage; Mohs hardness 3, trigonal crystal system, specific gravity about 2.71. It may show double refraction through clear areas and effervesces strongly in dilute hydrochloric acid.

Identified September 22, 2026More mineral →

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Physical properties

Formation & geological history

Forms in sedimentary carbonate deposits, hydrothermal veins, caves, and metamorphosed limestones; many collector pieces formed during relatively young to ancient sedimentary or hydrothermal events. The blocky shape reflects natural cleavage, though this specimen appears partly cut or trimmed.

Uses & applications

Used for ornamental specimens, optical demonstrations, teaching, and limited decorative carving; calcite is industrially important in cement, lime, aggregate, paper, and acid-neutralizing products.

Geological facts

Calcite has three perfect cleavage directions and is commonly confused with gypsum, which is softer and does not fizz in acid. Clear optical calcite is especially prized for its strong birefringence.

Field identification & locations

Identify by rhombohedral cleavage, low hardness, acid reaction, and double refraction; common sources include Mexico, Iceland, Brazil, China, and the United States. Avoid scratching or washing with acid if preservation matters.