The ledge was covered with heavy ash, called tephra, and speckled with droplets of volcanic glass and delicate lava threads known as Pele's hair.
A natural volcanic glass similar to obsidian But having distinctive concentric cracks and a relatively high water a fluffy heat - expanded form perlite is used as a lightweight aggregate, in fire - resistant insulation, and in soil for potted plants.
Smectite mainly came from the alteration of volcanic ash or volcanic glass and the weathering materials derived from land rocks.
Any of various volcanic glasses distinguished by their dull pitchlike luster.
But in 2008, an analysis of a handful of lunar volcanic glass beads suggested they might have formed in a watery environment.
volcanic rock includes the volcanic glass obsidian.
A usually black or banded, hard volcanic glass that displays shiny, curved surfaces when fractured and is formed by rapid cooling of lava.
