Mohs Scale of Hardness

Mohs Scale Of Hardness		Common Items For Comparison
1	Talc	1	pencil lead (graphite)
2	Gypsum	2.5	fingernail
3	Calcite	3.5	copper penny, coral
4	Fluorite
5	Apatite	5.5	turquoise, opal, glass, knife blade
6	Orthoclase (feldspar)	6.5	jasper, tanzanite, peridot, steel file
7	Quartz (amethyst, citrine)	7.5	emerald, aquamarine, garnet
8	Topaz	8	spinel
9	Corundum (ruby and sapphire)
10	Diamond

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Database and system administration by Gregory Brutsche.