Mineral Created From Volcanic Rock
This page is the CodyCross answer for the clue below from Resorts, Group 559, Puzzle 5 (Tennis Lessons).
Question is: Mineral Created From Volcanic Rock
and the answer is: PERLITE
Word Meaning:
PERLITE — (mineralogy) An amorphous volcanic glass formed by the hydration of obsidian.
Definitions from Wiktionary.