Crossword clues for the word: OBSIDIAN The word OBSIDIAN has appeared as an answer to at least 9 crossword clues on different crossword puzzles. Crossword clues for OBSIDIAN Showing 1 to 9 of 9 results Clue(s) Dark glass formed by cooling lava Dark glassy volcanic rock also called Iceland agate Dark volcanic glass Dark volcanic rock Hard rock outside broadcast with two chaps Relative of perlite Some European aid is boxed up as result of volcanic activity Volcanic glass Volcanic rock