mineral

Tumbled pale quartz or calcite pebble

Likely quartz (SiO₂) or calcite (CaCO₃)

AI-generated identification · may be incorrect

Small, rounded, cream-colored specimen with a dull to waxy luster and possible translucent edges. Quartz has Mohs hardness 7 and no cleavage; calcite has hardness 3, prominent cleavage, and fizzes in dilute hydrochloric acid.

Identified August 25, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed in a hydrothermal vein or sedimentary carbonate deposit, then naturally or mechanically rounded; its geological age cannot be determined from the photograph.

Uses & applications

Quartz is used in glass, electronics, abrasives, and decorative objects; calcite is used in cement, lime, construction aggregate, and ornamental stone. This small piece has modest decorative or teaching value.

Geological facts

A hardness test and acid test readily distinguish the two: quartz scratches glass and does not fizz, while calcite is easily scratched with a steel knife and effervesces in acid.

Field identification & locations

Common worldwide, especially in quartz veins, river gravels, and limestone regions. Inspect for glass-scratching ability, cleavage, translucency, and acid reaction; avoid destructive testing on valuable specimens.