Definition

1. Noun:
   • A grey volcanic rock containing plagioclase and quartz and other crystalline minerals: Dacite is a type of igneous rock formed from volcanic lava. It is typically light grey in color and has a composition between that of rhyolite and andesite, characterized by the presence of plagioclase feldspar and quartz crystals.

Usage Examples

• Noun:
  • The mountain's peak is composed primarily of dacite.
  • Geologists analyzed the dacite to understand the volcano's history.

Advanced Usage

• In geological classification: Dacite is classified based on its specific mineral content and silica percentage, which is typically high (between 63% and 68%).
  • The lava dome was formed by the slow extrusion of viscous dacite.

Variants and Related Words

• Dacitic (adj): Pertaining to or having the composition of dacite.
  • The dacitic lava flow cooled slowly, forming a distinctive texture.

Synonyms

• Volcanic rock: A general term for rocks formed from lava.
• Felsic rock: A category of light-colored igneous rocks rich in silica, which includes dacite, rhyolite, and granite.

Related Terms (Not Phrasal Verbs or Idioms)

• Plagioclase: A series of feldspar minerals commonly found in dacite.
• Quartz: A hard, crystalline mineral made of silicon dioxide, a key component of dacite.
• Lava dome: A mound-shaped structure often formed by the eruption of viscous lava like dacite.

Noun

1. a grey volcanic rock containing plagioclase and quartz and other crystalline minerals