Enter a clue or pattern or both:
The Clue
7 on the Mohs scale (6 letter answer)
The Answer
QUARTZ
Tags
Notes
The answer QUARTZ is rarely seen, appearing only about once every 1600 puzzles.
Related Clues
Amethyst or sandstone
Hard rock
Basis for some watches
Sand's main ingredient
Seven on the Mohs' scale
Tiger's-eye, essentially
What a crystal ball gazer sees
Definition
QUARTZ as a noun:
1. (quartz glass, quartz, vitreous silica, lechatelierite, crystal) = colorless glass made of almost pure silica
2. a hard glossy mineral consisting of silicon dioxide in crystal form; present in most rocks (especially sandstone and granite); yellow sand is quartz with iron oxide impurities