Meaning of Mohs scale

Mohs' scale"

Pronunciation: (mōz), [key]
  1. a scale of hardness used in mineralogy. Its degrees, in increasing hardness, are: talc 1; gypsum 2; calcite 3; fluorite 4; apatite 5; feldspar 6; quartz 7; topaz 8; sapphire 9; diamond 10. Abbr.: MSH
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.