A dark blue or black mineral of the amphibole group, occurring chiefly in alkaline igneous rocks or as blue asbestos (crocidolite).
More example sentences
- Willman reported astrophyllite, biotite, molybdenite, and riebeckite associated with smoky quartz and microcline (variety amazonite) on Mount Kineo at North Cheyenne Canyon.
- Later in the week we enticed the government guys to take us to a locality called Kent, quite a drive from Karaganda, where in a beautiful setting we collected fluorite, riebeckite, and zircon from granite.
- Glaucophane and riebeckite are found in low-grade schists of basic igneous parentage; crocidolite occurs in medium-grade metamorphosed ironstones.
late 19th century: from the name of Emil Riebeck (died 1885), German explorer, + -ite1.
Definition of riebeckite in:
- The US English dictionary