Linked from
The 62 pages that link to Calcium carbonate, each with the reason it gives.
CalciteNarrower topic: Calcite is one crystalline form of this compound.
AragoniteNarrower topic: Aragonite is one crystalline form of this compound.
ChalkNarrower topic: Chalk is a rock built predominantly from this compound.
TravertineNarrower topic: Travertine forms when dissolved calcium carbonate precipitates from water.
Mollusc shellNarrower topic: It supplies most of the mineral matter in many mollusc shells.