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. Cave Environments. Look for aragonite in caves, where it forms stalactites, stalagmites, and other speleothems, often alongside calcite. Aragonite speleothems tend to be more delicate and needle-like.
2. Hot Spring Deposits. Examine areas around hot springs and geysers for tufa deposits, which can contain aragonite.
3. Serpentinite Occurrences. Aragonite can be found in veins within serpentinite rocks, often associated with other secondary minerals.
4. Fossil Shells. Many modern and some fossil mollusk shells are composed of aragonite. However, older fossil shells often show aragonite that has inverted to calcite.
5. Hydrothermal Veins. Search for aragonite in hydrothermal veins, particularly in areas with low-temperature fluid circulation.
6. Acid Test. Like calcite, aragonite will effervesce (fizz) vigorously when a drop of dilute hydrochloric acid (HCl) is applied, due to the release of carbon dioxide. This distinguishes it from many non-carbonate minerals.

Quick Check

Color:

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

Luster:

Vitreous to resinous

Streak:

White

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