Vaterite

[6] However, vaterite does occur naturally in mineral springs, organic tissue, gallstones, urinary calculi and plants.

In those circumstances, some impurities (metal ions or organic matter) may stabilize the vaterite and prevent its transformation into calcite or aragonite.

Vaterite can be produced as the first mineral deposits repairing natural or experimentally-induced shell damage in some aragonite-shelled mollusks (e.g. gastropods).

In 2018, vaterite was identified as a constituent of a deposit formed on the leaves of Saxifraga at Cambridge University Botanic Garden.

[7][8] Vaterite is tapped as an effective intermediate form of cement whose production consumes carbon dioxide rather than emitting it.

Crystal structure of vaterite
Vaterites of the locality San Vito (Monte Somma, Italy ) are microcrystalline with largest crystals below 2 mm size. This vaterite is epitactic after aragonite. The crystal contains triplet of aragonite inside of it. On its termination twin seams of aragonite triplet are well visible.