Very Hard Gemstone, Colorless or Pink
This page is the CodyCross answer for the clue below from Professions, Group 1540, Puzzle 5 (Civil Engineer).
Question is: Very Hard Gemstone, Colorless or Pink
and the answer is: DIAMOND
Word Meaning:
DIAMOND — (uncountable) A glimmering glass-like mineral that is an allotrope of carbon in which each atom is surrounded by four others in the form of a tetrahedron.
Definitions from Wiktionary.