Aphanite

Aphanites are commonly porphyritic, having large crystals embedded in the fine groundmass, or matrix. The larger inclusions are called phenocrysts. They consist essentially of very small crystals of minerals such as plagioclase feldspar, with hornblende or augite, and may contain also biotite, quartz, and orthoclase.

Common rocks that can be aphanitic

• Andesite
• Basalt
• Basanite
• Dacite
• Felsite
• Phonolite
• Rhyolite
• Trachyte