Definition

1. Noun:
   • A white or colored monoclinic feldspar: A common mineral of the feldspar group, typically white, pink, or colorless, and crystallizing in the monoclinic system. It is a key component of many igneous rocks like granite.

Usage Examples

• Noun:
  • The pink crystals in this granite are orthoclase.
  • Orthoclase is an important mineral used in the manufacture of porcelain and glass.

Advanced Usage

• In Petrology: Used to describe the potassium-rich feldspar in a rock's mineral composition.
  • The rock's composition was determined to be 60% quartz, 30% orthoclase, and 10% biotite.

Variants and Related Words

• Feldspar (n): The broader group of rock-forming minerals to which orthoclase belongs.
• Microcline (n): Another potassium feldspar mineral, but with a triclinic crystal structure, often confused with orthoclase.
• Sanidine (n): A high-temperature form of potassium feldspar, typically found in volcanic rocks.

Synonyms

• Potassium feldspar: A more general term for feldspars rich in potassium, including orthoclase, microcline, and sanidine.
• K-feldspar: An abbreviated chemical term synonymous with potassium feldspar.

Noun

1. a white or colored monoclinic feldspar