Normally Red, Impure, Opaque Silica
This page is the CodyCross answer for the clue below from Professions, Group 1524, Puzzle 1 (Helicopter Pilot).
Question is: Normally Red, Impure, Opaque Silica
and the answer is: JASPER
Word Meaning:
JASPER — (obsolete) Any bright-coloured kind of chalcedony apart from cornelian.
Definitions from Wiktionary.