A feldspar mineral common in siliceous igneous rocks, consisting of a sodium-rich plagioclase (with more calcium than albite).
More example sentences
- It is composed of quartz, oligoclase, and microcline, with minor garnet, biotite, muscovite and iron-oxides.
- Here it was found sparsely as rounded grains associated with pargasite, diopside, oligoclase and lazurite.
- They range from bytownite - labradorite in basalts and gabbros, andesine - oligoclase in diorites and andesites to albite in granites and rhyolites.
Definition of oligoclase in:
- The US English dictionary