Dark, Glassy Volcanic Rock
This page is the CodyCross answer for the clue below from Canada, Group 1275, Puzzle 2 (Gravy and Cheese Curds).
Question is: Dark, Glassy Volcanic Rock
and the answer is: OBSIDIAN
Word Meaning:
OBSIDIAN — (mineralogy) A type of naturally occurring black glass produced by volcanoes.
Definitions from Wiktionary.