1. a common feldspar mineral consisting of potassium aluminum silicate, typically pink or white in color
Usage: geology; mineralogy

Examples

• The granite contained large crystals of orthoclase feldspar.
• Orthoclase is one of the most abundant minerals in the Earth’s crust.
• The pink color of the rock was due to orthoclase crystals.
• Geologists identified orthoclase in the igneous rock sample.
• Orthoclase weathers more slowly than plagioclase feldspar.
• The pottery glaze contained ground orthoclase as a flux.