Where is Aragonite found?

Aragonite occurs in specific geological environments. Knowing where to look, and in what kind of rock, is the difference between going home empty-handed and finding a great specimen.

Where to find Aragonite

Collecting tips

1. Look in Caves and Hot Springs. Aragonite frequently forms in cave environments as speleothems (stalactites, stalagmites, 'cave flowers') and around hot springs due to rapid precipitation from supersaturated waters.
2. Examine Sedimentary Rocks. Check for aragonite in recent marine sediments, oolitic limestones, and the shells of modern marine organisms (e.g., mollusks, corals).
3. Hydrothermal Veins. Explore areas with hydrothermal activity, as aragonite can precipitate from low-temperature hydrothermal solutions.
4. Serpentinite Occurrences. Aragonite can be found in serpentinized ultramafic rocks, often associated with other carbonate minerals.
5. Acid Test. Like calcite, aragonite will effervesce vigorously in dilute hydrochloric acid (HCl). This distinguishes it from many other non-carbonate minerals. However, it does not distinguish it from calcite.
6. Hardness Test. Aragonite has a Mohs hardness of 3.5-4, which is slightly harder than calcite (3). This can be a subtle but useful distinguishing feature if a clean crystal face is available for testing.

Quick Check

Color:

White, colorless, gray, yellow, green, blue, violet, brown

Luster:

Vitreous to resinous

Streak:

White

Explore Aragonite