Transparent Quartz
This page is the CodyCross answer for the clue below from Under the sea, Group 21, Puzzle 3.
Question is: Transparent Quartz
and the answer is: CRYSTAL
Word Meaning:
CRYSTAL — (countable) A solid composed of an array of atoms or molecules possessing long-range order and arranged in a pattern which is periodic in three dimensions.
Definitions from Wiktionary.