redruthite
/ˌrɛdˈruːθʌɪt/ /ˈrɛdruθʌɪt/Mineralogy. Now rare
noun
A dark grey or black copper ore mineral. Now usually called chalcocite.
- The mineral is a sulphide of copper, Cu2S. Crystal system: orthorhombic..
Origin
Mid 19th century; earliest use found in James Nicol (1810–1879), geologist. From Redruth, the name of a town in Cornwall, where the mineral was first found + -ite.