mineral

Botryoidal Aragonite (Cave Popcorn)

Aragonite (Calcium Carbonate, CaCO3)

Hardness: 3.5–4.0 on Mohs scale. Color: White, cream, or tan. Luster: Vitreous to dull. Crystal structure: Orthorhombic (often forming round, grape-like clusters known as botryoidal growth). Specific Gravity: 2.9–3.0.

Hardness: 3
Color: White, cream, or tan
Luster: Vitreous to dull

Identified March 7, 2026More mineral →

Identify your own rocks.

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

App Store Google Play

Physical properties

Formation & geological history

Formed through the precipitation of calcium carbonate from mineral-rich water. This specific variety often grows in cave systems or hot springs where slow evaporation or CO2 loss occurs. Age can range from Holocene to much older depending on the geological setting.

Uses & applications

Predominantly used as display specimens for collectors and in educational geology sets. Occasionally used in the manufacturing of cement or as a source of calcium in animal feed, though high-quality specimens are kept for the mineral trade.

Geological facts

This bubbly appearance is often referred to as 'Cave Popcorn'. Aragonite is chemically identical to calcite (polymorphs), but it has a different crystal structure. Over long periods of time and with heat, aragonite naturally converts into calcite.

Field identification & locations

Identify in the field by its distinctive 'popcorn' or 'grape' texture and reaction (effervescence) to weak hydrochloric acid. Commonly found in limestone caves or near carbonate-rich geothermal vents. Collectors should look for undamaged, clean clusters with distinct rounded shapes.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral

Epidote

Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)

mineral