Orthoclase is a common constituent of most granites and other felsic igneous rocks and often forms huge crystals and masses in pegmatite.

While slowly cooling within the earth, sodium-rich albite lamellae form by exsolution, enriching the remaining orthoclase with potassium.

[8] Together with the other potassium feldspars, orthoclase is a common raw material for the manufacture of some glasses and some ceramics such as porcelain, and as a constituent of scouring powder.

Some intergrowths of orthoclase and albite have an attractive pale luster and are called moonstone when used in jewelry.

In gemology, their luster is called adularescence and is typically described as creamy or silvery white with a "billowy" quality.