Calcareous (adjective)

1. Of or relating to limestone or lime; containing or impregnated with lime.
2. Of or relating to the shells of mollusks, which are made of calcium carbonate.

Origin:

From latin calcareus, from calx ("lime").

Examples:

1. The calcareous soil was rich in nutrients and ideal for growing certain crops.
2. Calcareous rocks are formed from the accumulation of shells and other marine debris.
3. The calcareous deposits in the cave walls were a result of centuries of water flow.
4. The calcareous shell of the mollusk was hard and durable.
5. Many ancient buildings and structures were made of calcareous stone.