plagioclase's Usage Examples:

plagioclase feldspar group.

Labradorite is a specific mineral, a calcic member of the plagioclase feldspar group.

mafic igneous rock consisting of plagioclase feldspar and pyroxene.

The plagioclase often shows very thin exsolution lamellae of potash feldspar, but nevertheless the original bulk chemical composition was probably low in potassium.

Granite is a lighter colored igneous rock containing relatively large crystals of the minerals plagioclase, quartz and alkali feldspars such as orthoclase.

The black gabbro contains pyroxene and pigmented plagioclase feldspars.

The same approach is now being applied to hornblende and plagioclase from amphibolite facies shear zones.