Aragonite
A second form of calcium carbonate, found in some CM chondrites.
Key facts
- Formula
- CaCO3
- Family
- Carbonates, sulphates, salts and weathering products
- Crystal system
- Orthorhombic
What it is
Aragonite has the same chemistry as calcite but a denser structure. On Earth it forms shells and pearls.
Where it is found
It occurs as grains in some CM chondrites, alongside calcite. The pair gives clues to the chemistry of the water in the parent asteroid, because aragonite tends to form in water rich in magnesium.
How it is recognised
It is identified by Raman spectroscopy or X-ray diffraction.
Did you know?
Did you know?
Mother-of-pearl in shells is made of aragonite.
Did you know?
Aragonite slowly changes to calcite over geological time on Earth.