Crosswordiee.com

% replaces any number of letters (la% - lake, lamp)_ replaces one letter (ca_ - car, cat)

Crossword clues for 7 on the Mohs scale:

TOPAZ: 7 on the Mohs scale
QUARTZ: 7 on the Mohs scale
QUARTZ: It's 7 on the Mohs scale of hardness