Plagioclase (/ˈplædʒ(i)əˌkleɪs, ˈpleɪdʒ-, -ˌkleɪz/ PLAJ-(ee)-ə-klayss, PLAYJ-, -⁠klayz) is a series of tectosilicate (framework silicate) minerals within...

potassium, or barium. The most common members of the feldspar group are the plagioclase (sodium-calcium) feldspars and the alkali (potassium-sodium) feldspars...

and plagioclase makes up more than 65% of the total feldspar content. Gabbroids are distinguished from dioritoids by an anorthite (calcium plagioclase) fraction...

quartz in plagioclase. The intergrowths are microscopic in scale, typically with maximum dimensions less than 1 millimeter. The plagioclase is sodium-rich...

effect (schiller). Labradorite is an intermediate to calcic member of the plagioclase series. It has an anorthite percentage (%An) of between 50 and 70. The...

plagioclase phenocrysts, but 4% olivine microphenocrysts, might be termed an aphyric to sparsely plagioclase-olivine phyric basalt, where plagioclase...

phaneritic, intrusive igneous rock characterized by its composition: mostly plagioclase feldspar (90–100%), with a minimal mafic component (0–10%). Pyroxene...

sodic plagioclase (An70–85), norites (plagioclase-orthopyroxene), and gabbronorites (plagioclase-clinopyroxene-orthopyroxene) with similar plagioclase compositions...

intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides...

(lamellae) of different alkali feldspars (orthoclase and sodium-rich plagioclase). Polished moonstones often display chatoyancy ("cat's eye" effect),...