peridotite
noun
pe·ri·do·tite pə-ˈri-də-ˌtīt 
: any of a group of granular igneous rocks composed of ferromagnesian minerals and especially olivine
peridotitic
pə-ˌri-də-ˈti-tik
adjective 
Example Sentences
Recent Examples on the Web In Oman, vast ridges of a mineral called peridotite mineralize CO2 from the air, forming white veins resembling marbling in steak. 
Robert F. Service, Science | AAAS, 3 Sep. 2020
Robert F. Service, Science | AAAS, 3 Sep. 2020 Word History
Etymology
French péridotite, from péridot
First Known Use
1882, in the meaning defined above