Linked from
The 9 pages that link to Orthoclase, each with the reason it gives.
FeldsparBroader topic: It is a common potassium-rich feldspar in granites and other rocks.
MoonstoneRelated: Orthoclase forms one of the intergrown feldspar phases in classic moonstone.
Alkali feldsparBroader topic: It is a familiar potassium-rich member of the alkali-feldspar group.
PerthiteRelated: Orthoclase is one common potassium-rich host for albite in perthite.
MicroclineCompared with: Its symmetry and degree of ordering distinguish it from microcline.