coccolite
/kɒkəlaɪt, kɑk-/ (UK) /kɑkəlaɪt, kɑk-/ (US)
Definitions
1. noun
A type of sedimentary rock formed from the accumulation and cementation of coccoliths (the calcium carbonate or other shells of coccolithophores, small marine algae).
“The geologist studied the coccolite samples under a microscope to analyze their composition.”