1Mineralogy. A brown variety of staurolite rich in manganese.
2Geology. A syenite composed mainly of microperthite, with lesser amounts of quartz and usually oligoclase and biotite, and characterized by a trachytoid or granitic texture.
Origin
Mid 19th century; earliest use found in James Dana (1813–1895), geologist, zoologist, and teacher. In sense 1 from Nordmark, the name of an area in Sweden + -ite.