Rock Identifier
Botryoidal blue-green mineral specimen, likely hemimorphite (Hemimorphite, Zn4Si2O7(OH)2·H2O; possibly associated with calcite or smithsonite) — mineral
mineral

Botryoidal blue-green mineral specimen, likely hemimorphite

Hemimorphite, Zn4Si2O7(OH)2·H2O; possibly associated with calcite or smithsonite

AI-generated identification · may be incorrect

Pale blue-green, white, and botryoidal/granular with a vitreous to pearly luster. Hemimorphite has Mohs hardness 4.5–5, orthorhombic crystals, uneven fracture, and specific gravity about 3.4–3.5. The image is not sufficient to confirm cleavage or exact mineral identity.

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Physical properties

Pale blue-green, white, and botryoidal/granular with a vitreous to pearly luster. Hemimorphite has Mohs hardness 4.5–5, orthorhombic crystals, uneven fracture, and specific gravity about 3.4–3.5. The image is not sufficient to confirm cleavage or exact mineral identity.

Formation & geological history

Typically forms as a secondary zinc-ore mineral in oxidized zones of carbonate-hosted lead-zinc deposits, generally through relatively recent weathering of sulfide ores. Around 48.9°N, 2.5°E, such a specimen is more likely imported or collected from a mineral locality elsewhere than locally formed.

Uses & applications

Primarily a collector specimen; attractive blue varieties may be cut as ornamental material, though they are too soft and brittle for most jewelry. Associated zinc deposits have industrial importance.

Geological facts

Its characteristic botryoidal surfaces can resemble turquoise, smithsonite, or blue-green aragonite. Confirmatory testing requires hardness, specific gravity, streak, acid reaction, or laboratory analysis.

Field identification & locations

Look for lightweight-looking white-to-blue botryoidal crusts in oxidized zinc deposits. Smithsonite is the main alternative and may be more likely if the material is distinctly waxy or shows stronger curved globular masses; avoid acid testing on valuable specimens.