Calcium carbonate crystallises two common ways. Calcite and aragonite carry the same formula, CaCO₃, and assemble it differently inside. That structural difference is why aragonite is denser and slightly harder than calcite despite being chemically identical.
This slice is the aragonite side of that split. It formed in karst cavities in Cambrian limestone at Ighoud, western Morocco, where carbonate-carrying water moved through rock and left mineral behind in layers.
Cut across the growth direction, the banding becomes readable. Uncut, the same piece is a lump.
Carbonates are soft. Keep it dry and dust rather than wash.
Mineral: Aragonite (calcium carbonate, CaCO₃)
Crystal system: Orthorhombic
Origin: Ighoud (Irhoud), Youssoufia Province, Morocco
Hardness: 3.5 to 4 on the Mohs scale, soft and easily marked
Treatment: Cut and polished, no dye or heat
Dimensions: 6.98 x 1.4 x 8 cm
Weight: 91.02g
You will receive the exact piece photographed.