Re: How do aragonite crystals form?

Message ID#: 887154170.Es

How do aragonite crystals form?

Ciarra:

Aragonite (CaCO₃) is a carbonate mineral (it contains carbon joined to three oxygens - CO₃^2-). It is a polymorph of the much more common mineral, calcite. That is, it has the same chemical composition, but a different atomic structure (it's composed of the same stuff, the atoms are just arranged differently).

Aragonite forms primarily by (1) high pressure, low temperature metamorphism (application of heat, pressure, and/or chemically-active fluids to pre-existing rocks below the earth's surface), (2) precipitation (chemical deposition) from warm ocean waters, (3) as part of the carbonate skeleton of some marine animals (for example, snails and clams) and plants (algae), and (4) in hot springs.

Pearls (produced by oysters -- a type of clam) are aragonite, as is the mother-of-pearl coating on shells.

I hope this information helps. If you want to know anything further don't hesitate to contact me.