Friedrich Mohs, in 1812, arranged ten minerals in order of hardness, so that each will scratch those lower in the scale, thus: Scratch hardness (Mohs) Mineral used for comparison Simple hardness tester 1 Talc Gypsum Calcite Fluorite Apatite Orthoclase Quartz Topaz Corundum Diamond Can be scratched with fingernail 2 Can be scratched with fingernail 3 Can be scratched with copper coin 4 Easily scratched with knife 5 Can be scratched with knife 6 Can be scratched with steel file 7 Scratches window glass 8 9 10 Chalk is a very pure limestone formed of calcite, containing only small amount of silt or mud.
(Scratch hardness (Mohs) Mineral used for comparison; Can be scratched; ) Context(Scratch hardness ( Mohs ) Mineral used for comparison Can be scratched,List([127, 368))):(Friedrich Mohs; arranged; ten minerals; T:in 1812) (a very pure limestone; formed; of calcite) (each; will scratch thus; L:in the scale) (Easily; scratched; ) (Simple hardness tester 1 Talc Gypsum Calcite Fluorite Apatite Orthoclase Quartz Topaz Corundum Diamond Can be scratched with fingernail 2 Can be scratched with fingernail 3 Can be scratched with copper coin 4 Easily scratched with knife 5 Can be scratched with knife 6 Can be scratched with steel file 7 Scratches window glass 8 9 10 Chalk; is; a very pure limestone formed of calcite) (Scratch hardness; used; for comparison) (copper coin 4; Can be scratched; ) (1 Talc Gypsum Calcite Fluorite Apatite Orthoclase Quartz Topaz Corundum Diamond; Can be scratched; ) (Simple hardness tester 1 Talc Gypsum Calcite Fluorite Apatite Orthoclase Quartz Topaz Corundum Diamond Can be scratched with fingernail 2 Can be scratched with fingernail 3 Can be scratched with copper coin 4 Easily scratched with knife 5 Can be scratched with knife 6 Can be scratched with steel file 7 Scratches window glass 8 9 10 Chalk; containing; only small amount of silt or mud) (Simple hardness tester; Can be scratched; with fingernail 3)
Scratch hardness ( Mohs ) Mineral used for comparison Can be scratched,List([127, 368))
Scratch hardness (Mohs) Mineral used for comparison Friedrich Mohs a very pure limestone each Easily Simple hardness tester 1 Talc Gypsum Calcite Fluorite Apatite Orthoclase Quartz Topaz Corundum Diamond Can be scratched with fingernail 2 Can be scratched with fingernail 3 Can be scratched with copper coin 4 Easily scratched with knife 5 Can be scratched with knife 6 Can be scratched with steel file 7 Scratches window glass 8 9 10 Chalk Scratch hardness copper coin 4 1 Talc Gypsum Calcite Fluorite Apatite Orthoclase Quartz Topaz Corundum Diamond Simple hardness tester 1 Talc Gypsum Calcite Fluorite Apatite Orthoclase Quartz Topaz Corundum Diamond Can be scratched with fingernail 2 Can be scratched with fingernail 3 Can be scratched with copper coin 4 Easily scratched with knife 5 Can be scratched with knife 6 Can be scratched with steel file 7 Scratches window glass 8 9 10 Chalk Simple hardness tester
Can be scratched arranged formed will scratch thus scratched is used Can be scratched Can be scratched containing Can be scratched
ten minerals T:in 1812
of calcite
L:in the scale
a very pure limestone formed of calcite
for comparison
only small amount of silt or mud
with fingernail 3