Wiktionary
otwayite
n. (context mineralogy English) A green orthorhombic hydrated nickel carbonate mineral.
Wikipedia
Otwayite
Otwayite, NiCO(OH), is a hydrated nickel carbonate mineral. Otwayite is green, with a hardness of 4, a specific gravity of 3.4, and crystallises in the orthorhombic system.