Calcarenite

Part of speech: noun

Definitions

1. A sedimentary rock composed of cemented sand-sized grains of calcium carbonate, often derived from shell or coral fragments
2. A limestone formed from consolidated particles of calcium carbonate that were deposited as loose sand and later hardened
3. Rock of the calcareous sandstone type, built from lithified grains of carbonate material such as broken marine shells

Etymology: Calcarenite is a technical coinage, not an ancient word. It combines Latin "calcarius", meaning "of lime" or "limy", from "calx", "lime", with the English "arenite", a sandstone-type term built on Latin "arena", "sand". The sense is a sedimentary rock made mostly of sand-sized grains of calcium carbonate, such as shell fragments and coral debris, rather than quartz. The word belongs to the vocabulary of geology, where scientists formed a family of names for rocks by attaching "-arenite" to a description of the grains they contain. The pattern lets a geologist name a sandstone by its composition at a glance: "quartzarenite" for quartz-rich sand, and "calcarenite" for lime-rich sand. Because the term was built from parts to describe a rock type that had not been named before in that precise way, its history is a matter of modern scientific naming rather than of everyday speech.