Gemstone; One of December's Modern Birthstones
This page is the CodyCross answer for the clue below from Science Lab, Group 312, Puzzle 1 (Decomposition).
Question is: Gemstone; One of December's Modern Birthstones
and the answer is: ZIRCON
Word Meaning:
ZIRCON — (uncountable) A mineral occurring in tetragonal crystals, usually of a brown or grey colour and consisting of silica and zirconia.
Definitions from Wiktionary.