Aragonite is metastable at surface conditions, which means that given enough time it converts to calcite, the more stable form of the same compound. That is why aragonite turns up in geologically recent settings like caves, hot springs and living shells, and gets scarcer the further back in the record you look.
A slice like this is a mineral caught part-way through a change it has not finished. Nothing will happen to it on a shelf in a human lifetime. On a geological one, it will not survive as aragonite.
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: 10.79 x 9.06 x 1.45 cm
Weight: 153.2 g
You will receive the exact piece photographed.