Mollusc shells, pearls and coral skeletons are built largely from aragonite. Animals use it because it precipitates readily from seawater at the temperatures they live in.
This slice is the same mineral arrived at without biology. Water moving through limestone at Ighoud deposited it in layers inside karst cavities, no organism involved. Same compound, same crystal system, completely different route.
Nothing here is shell. It is the inorganic version of the material a shell is made from.
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: 12.15 x 7 x 2.22 cm
Weight: 194.69 g
You will receive the exact piece photographed.