mineral
Botryoidal aragonite (cave calcite/aragonite formation)
Aragonite, CaCO₃; possibly mixed with calcite and iron-oxide staining
AI-generated identification · may be incorrectCream to tan, botryoidal and cauliflower-like crust with mammillary growths, porous cavities, and dull to pearly luster. Mohs hardness 3.5–4; orthorhombic aragonite has imperfect cleavage, specific gravity about 2.9–3.0, and effervesces in dilute hydrochloric acid.
Identified More mineral →
Explore Botryoidal aragonite (cave calcite/aragonite formation) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Cream to tan, botryoidal and cauliflower-like crust with mammillary growths, porous cavities, and dull to pearly luster. Mohs hardness 3.5–4; orthorhombic aragonite has imperfect cleavage, specific gravity about 2.9–3.0, and effervesces in dilute hydrochloric acid.
Formation & geological history
Forms when calcium-carbonate-rich groundwater precipitates in caves, cavities, springs, or fractures; iron oxides create brown coloration. The specimen’s exact age cannot be determined visually and may range from recent to Quaternary.
Uses & applications
Primarily a collector specimen; attractive pieces may be used decoratively, but aragonite is too soft and fragile for most jewelry or construction applications.
Geological facts
Botryoidal means rounded, grape-like aggregates produced by repeated mineral growth. Aragonite is metastable and can slowly transform into the more stable calcite under suitable conditions.
Field identification & locations
Identify by rounded carbonate growths, porous cave-like texture, low hardness, and acid fizz; distinguish from chalcedony by its stronger acid reaction and softness. Common in karst caves and hydrothermal cavities worldwide.
