Enter a clue or pattern or both:
The Clue
Mineral used in making refractories (10 letter answer)
The Answer
CHRYSOLITE
Tags
Notes
The answer CHRYSOLITE is so rare that it appears less than once every 2500 puzzles.
Definition
CHRYSOLITE as a noun:
1. a brown or yellow-green olivine found in igneous and metamorphic rocks and used as a gemstone