How is plagioclase feldspar different from orthoclase feldspar?
Simply so, what is the main difference between orthoclase feldspar and plagioclase feldspar?
Plagioclase feldspars lack potassium, are light colored and are usually striated. The other k-spar minerals are sanidine, microcline and anorthoclase . Orthoclase is the more common of the k-spars. The differences between these minerals are minor in hand samples.
Correspondingly, is plagioclase a feldspar?
Plagioclase is a member of the feldspar group (like orthoclase) and is a framework silicate. Plagioclase consists of a solid solution between the albite and anorthite end-members, and together with quartz is the most common of the rock forming minerals.
The feldspars are divided into two main groups: Potassium feldspar ("K-spar") and plagioclase ("plag").