Gemstone Hardness

Friedrich Mohs, a German mineralogist, developed the Mohs Scale in 1812. He selected ten minerals of distinctly different hardness that ranged from a very soft mineral (talc) to a very hard mineral (diamond). With the exception of diamond, the minerals are all relatively common and relative easy and inexpensive to obtain.

The Mohs Hardness Test is one of the most important tests for identifying mineral specimens. The test compares the resistance of a mineral to being scratched by the ten reference minerals in the Mohs Hardness Scale. The test is useful because most specimens of a given mineral are very close to the same hardness. This makes hardness a reliable diagnostic property for most minerals.

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Gemstone Hardness
Diamond 10
Corundum(Ruby and Sapphire) 9
Chrysoberyl 8.5
Topaz 8
Beryl 7.5 to 8
Spinel 7.5 to 8
Zircon 7.5
Tourmaline 7 to 7.5
Quartz 7
Garnet 6.5 to 7.5
Jadeite 6.5 to 7
Sillimanite 6.5 to 7.5
Spodumene 6.5 to 7
Zoisite(Tanzanite) 6 to 7
Orthoclase 6 to 6.5
Prehnite 6 to 6.5
Pyrite 6 to 6.5
Diopside 5.5 to 6.5
Nephrite 5 to 6
Turquoise 5 to 6
Apatite 5
Kyanite 4.5 to 5 or 7
Fluorite 4
Dolomite 3.5 to 4
Malachite 3.5 to 4
Rhodochrosite 3.5 to 4
Sphalerite 3.5 to 4
Serpentine 3 to 5
Gold 2.5 to 3
Silver 2.5 to 3

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