1. Plural of orthoclase; a common feldspar mineral composed of potassium aluminum silicate, typically white, pink, or colorless, used in ceramics and glassmaking.
Usage: technical; mineralogy

Examples

• Orthoclases are among the most abundant minerals in Earth's continental crust.
• The geologist identified several orthoclases in the granite sample under the microscope.
• Orthoclases contribute to the pink coloration of some granites.
• Ceramic manufacturers value orthoclases for their role in producing durable pottery.
• The crystal structure of orthoclases makes them useful in industrial applications.