mineral

Likely calcite or limestone fragment

Calcite (CaCO₃), possibly limestone dominated by calcite

AI-generated identification · may be incorrect

Pale cream, earthy to dull luster, irregular fracture, and apparently fine-grained texture; calcite has Mohs hardness 3, rhombohedral cleavage, and specific gravity about 2.71. The image alone cannot confirm cleavage or mineral identity.

Identified September 8, 2026More mineral →

Explore Likely calcite or limestone fragment in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Likely formed by chemical or biological precipitation of calcium carbonate in a marine sedimentary environment, later broken from a larger piece; age is indeterminate and may range from recent to hundreds of millions of years.

Uses & applications

Limestone is widely used for cement, aggregate, agricultural lime, and stone; clear or well-crystallized calcite is collected, while this rough fragment has little commercial value.

Geological facts

Calcite effervesces vigorously with dilute hydrochloric acid or household vinegar, especially when powdered. Limestone commonly contains fossils or impurities that produce cream, tan, or gray colors.

Field identification & locations

Look for strong fizz with dilute acid, very low hardness, and rhombohedral cleavage; it can scratch with a steel nail but not glass. Common worldwide, especially in former shallow-marine basins.