Aphanite

: They are often composed of very small crystals of minerals like plagioclase feldspar, augite, or hornblende.

: When lava reaches the Earth's surface or shallow subsurface (hypabyssal environments), it cools too quickly for large crystals to grow. aphanite

: Because they form near the surface, they may contain small holes (vesicles) created by escaping gas bubbles during the cooling process. APHANITE Definition & Meaning - Dictionary.com : They are often composed of very small