- a blue to dark-gray mineral near the anorthite end of the plagioclase feldspar group.
Origin of bytownite
Examples from the Web for bytownite
Historical Examples of bytownite
These consist of hornblende (dark green) and basic plagioclase felspar, labradorite and bytownite (grey or nearly white).
The felspar ranges from bytownite to oligoclase, being usually a variety of labradorite; orthoclase is scarce.
Isolated crystals of bytownite bounded by well-defined faces are unknown.
These intermediate members are the lime-soda felspars known as oligoclase, andesine, labradorite and bytownite.
- A bluish to dark gray triclinic mineral of the plagioclase feldspar group that contains a higher proportion of calcium than sodium. Bytownite occurs in alkaline igneous rocks. Chemical formula: (Ca,Na)(Si,Al)4O8.