Assertion: anorthite | /r/HasProperty | a calcium feldspar
Facets:
Source sentences:
text: Albite is a sodium feldspar, and anorthite is a calcium feldspar.
text: Anorthite (the calcium feldspar), though it contains twice as much alumina as soda and potash feldspars and also contains lime which is an important ingredient of glass, is not preferred in the glass industry because it is more refractory (p.c.e. 12).