perlite

About 0.11 uses per million words.

Meaning

1. noun An amorphous volcanic glass formed by the hydration of obsidian.
2. noun The lightweight insulating material and aggregate resulting from expanding perlite glass by heat.

Similar words

aggregate pearlite pitchstone pearlstone phonolite iolite imogolite obsidian praseolite pisolite

Often followed by

and or is to in aggregate are concrete as

Word family

perlites perlitic