Selected Minerals – Today: Aragonite

Aragonite

• Named after the type locality Aragon (Spain)
• One of the two naturally occuring forms of calcium carbonate (the other being calcite)
• Formula: CaCO₃
• Space group: Pmcn (No. 62)
• Crystal system: orthorhombic
• Crystal class: mmm
• Lattice parameters: a = 4.95 Å, b = 7.96 Å, c = 5.74, α = β = γ = 90°

---

Picture: Rob Lavinsky, iRocks.com – CC BY-SA 3.0

---

Crystal structure (click on the picture to download the VESTA file):

CO₃ triangles (black), CaO₉ irregular polyhedra (blue)

Advertisement