Mohs hardness scale for Gemstones

MOHS SCALE OF HARDNESS

The MOHS Hardness Scale starts with talc at 1 being the softest mineral and ending with diamond at 10 being the hardest mineral. It is universally used around the world as a way of distinguishing minerals. Simply put: the higher the number, the harder the mineral.

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10

Diamond

9

Corundum

8

Topaz

7

Quartz

6

Feldspar

5

Apatite

4

Fluorite

3

Calcite

2

Gypsum

1

Talc

The MOHS scale was created by trying to scratch one mineral with another, and then recording which mineral left a scratch. Fro example, Corundum (Sapphire and Ruby) was used to scratch Apatite. Corundum left a scratch on the surface of Apatite, and so this mineral should sit higher on the scale.

The most important number on this scale of 7. Why? 7 is the hardness of Quartz, which is the hardest mineral that is commonly air born. It is important to have jewelery with gemstones in it that have a MOHS of 7 or higher because of the amount of dust and impurities in the air. If the dust contains minute particles of Quartz, than any mineral that is below quartz on the MOHS scale will be scratched.

MOHS scale of hardness

So image you have a beautiful Apatite ring and you notice there is some dust on it. You grab a cloth and start to clean it. There is a high likely hood that there is something in that dust that is harder than Apatite (5). This means when you wipe the dust off the ring, it will scratch the Apatite gemstone.

This is why it is always advisable to wash your jewelery under warm water before you wipe it clean. that way most of the dust will be removed and you reduce the risk of scratches.

Gemstone Family Classification

The gemstones listed here show every color in the rainbow. Even with such variety of colors, patterns and shapes - they can be broken down into 16 different families based on their chemical composition. The MOHS hardness is shown for each of the more common gemstones.

Gemstone Name Specific Gravity Mohs Hardness Index of Refraction Gemstone Family
Achorite 3.03 - 3.25 7.0 - 7.5 Mohs 1.610-1.661 Tourmaline
Agate 2.65 7.0 Mohs 1.530 - 1.550 Quartz
Alexandrite 3.68 - 3.78 8.5 Mohs 1.746 - 1.755 Chrysoberyl
Almandine 3.50 - 4.30 6.5 - 7.5 Mohs 1.750 - 1.830 Garnet
Almandine Spinel 3.58 - 4.06 8.0 Mohs 1.708 - 1.735 Spinel
Almandine-Spessartine 3.50 - 4.30 6.5 - 7.5 Mohs 1.750 - 1.830 Garnet
Amazonite 2.55 - 2.76 6.0 - 6.5 Mohs 1.518 - 1.526 Feldspar
Amethyst 2.65 7.0 Mohs 1.532 - 1.554 Quartz
Andradite 3.50 - 4.30 6.5 - 7.5 Mohs 1.880 - 1.940 Garnet
Aquamarine 2.63 - 2.91 7.5 - 8.0 Mohs 1.567-1.590 Beryl
Balas Ruby 3.58 - 4.06 8.0 Mohs 1.708 - 1.735 Spinel
Black Opal 1.98 - 2.25 5.5 - 6.5 Mohs 1.440 - 1.460 Opal
Bloodstone 2.65 7.0 Mohs 1.535 - 1.539 Quartz
Brazilian Emerald 3.03 - 3.25 7.0 - 7.5 Mohs 1.610 - 1.640 Tourmaline
Cairngorm 2.65 7.0 Mohs 1.540 - 1.550 Quartz
Carnelian 2.65 7.0 Mohs 1.530 - 1.550 Quartz
Cat’s Eye 3.68 - 3.78 8.5 Mohs 1.746 - 1.755 Chrysoberyl
Chalcedony 2.65 7.0 Mohs 1.544 - 1.553 Quartz
Chlorspinel 3.58 - 4.06 8.0 Mohs 1.712 - 1.717 Spinel
Chrome Pyrope 3.50 - 4.30 6.5 - 7.5 Mohs 1.730 - 1.760 Garnet
Chrysoberyl 3.68 - 3.78 8.5 Mohs 1.746 - 1.755 Chrysoberyl
Chrysoprase 2.65 7.0 Mohs 1.530 - 1.550 Quartz
Citrine 2.65 7.0 Mohs 1.532 - 1.554 Quartz
Color-Change Garnet 3.50 - 4.30 6.5 - 7.5 Mohs 1.730 - 1.760 Garnet
Demantoid 3.50 - 4.30 6.5 - 7.5 Mohs 1.880 - 1.900 Garnet
Diamond 3.51 10 Mohs 2.417 Diamond
Dravite 3.03 - 3.25 7.0 - 7.5 Mohs 1.610-1.661 Tourmaline
Emerald 2.63 - 2.91 7.5 - 8.0 Mohs 1.560 - 1.605 Beryl
Feldspar 2.55 - 2.76 6.0 - 6.5 Mohs 1.518 - 1.572 Feldspar
Fire Opal 1.98 - 2.25 5.5 - 6.5 Mohs 1.430 - 1.460 Opal
Garnet 3.50 - 4.30 6.5 - 7.5 Mohs 1.730 - 1.760 Garnet
Ghanospinel 3.58 - 4.06 8.0 Mohs 1.712 - 1.747 Spinel
Goshenite 2.63 - 2.91 7.5 - 8.0 Mohs 1.570 - 1.600 Beryl
Green Quartz 2.65 7.0 Mohs 1.540-1.550 Quartz
Grossular 3.50 - 4.30 6.5 - 7.5 Mohs 1.880 - 1.940 Garnet
Heliodore 2.63 - 2.91 7.5 - 8.0 Mohs 1.570 - 1.600 Beryl
Heliotrope 2.65 7.0 Mohs 1.535 - 1.539 Quartz
Hessonite 3.50 - 4.30 6.5 - 7.5 Mohs 1.730 - 1.760 Garnet
Hyacinth 4.60 - 4.70 7.5 Mohs 1.777 - 1.987 Zircon
Indicolite 3.03 - 3.25 7.0 - 7.5 Mohs 1.610 - 1.640 Tourmaline
Jade 2.90 - 3.10 6.0 Mohs 1.640 - 1.667 Jade
Jadeite 2.90 - 3.10 6.0 Mohs 1.640 - 1.667 Jade
Jargon 4.60 - 4.70 7.5 Mohs 1.777 - 1.987 Zircon
Jasper 2.65 7.0 Mohs 1.540 - 1.550 Quartz
Labradorite 2.55 - 2.76 6.0 - 6.5 Mohs 1.560 - 1.572 Feldspar
Lapis Lazuli 2.70 - 2.90 5.0 - 5.5 Mohs 1.500 - 1.550 Lapis Lazuli
Malaia 3.50 - 4.30 6.5 - 7.5 Mohs 1.880 - 1.940 Garnet
Matura Diamond 4.60 - 4.70 7.5 Mohs 1.777 - 1.987 Zircon
Moonstone 2.55 - 2.76 6.0 - 6.5 Mohs 1.518 - 1.526 Feldspar
Morganite 2.63 - 2.91 7.5 - 8.0 Mohs 1.585 - 1.594 Beryl
Morion 2.65 7.0 Mohs 1.540 - 1.550 Quartz
Nephrite 2.90 - 3.10 6.0 Mohs 1.600 - 1.641 Jade
Onyx 2.65 7.0 Mohs 1.531 - 1.539 Quartz
Opal 1.98 - 2.25 5.5 - 6.5 Mohs 1.440 - 1.460 Opal
Orthoclase 2.55 - 2.76 6.0 - 6.5 Mohs 1.518 - 1.526 Feldspar
Peridot 3.22 - 3.45 7.0 Mohs 1.635 - 1.690 Peridot
Peristerite 2.55 - 2.76 6.0 - 6.5 Mohs 1.560 - 1.572 Feldspar
Praziolite 2.65 7.0 Mohs 1.540 - 1.550 Quartz
Pyrope 3.50 - 4.30 6.5 - 7.5 Mohs 1.730 - 1.760 Garnet
Pyrope-Almandine 3.50 - 4.30 6.5 - 7.5 Mohs 1.730 - 1.760 Garnet
Pyrope-Spessartine 3.50 - 4.30 6.5 - 7.5 Mohs 1.730 - 1.760 Garnet
Quartz 2.65 7.0 Mohs 1.544 - 1.553 Quartz
Red Beryl 2.63 - 2.91 7.5 - 8.0 Mohs 1.570 - 1.598 Beryl
Rhodolite 3.50 - 4.30 6.5 - 7.5 Mohs 1.740 - 1.770 Garnet
Rock Crystal 2.65 7.0 Mohs 2.000 Quartz
Rose Quartz 2.65 7.0 Mohs 1.540 - 1.550 Quartz
Rubellite 3.03 - 3.25 7.0 - 7.5 Mohs 1.610 - 1.640 Tourmaline
Rubicelle 3.58 - 4.06 8.0 Mohs 1.712 - 1.717 Spinel
Ruby 3.96 - 4.05 9.0 Mohs 1.757 - 1.779 Corundum
Sapphire 3.96 - 4.05 9.0 Mohs 1.757 - 1.779 Corundum
Sapphire Spinel 3.58 - 4.06 8.0 Mohs 1.712 - 1.747 Spinel
Siberite 3.03 - 3.25 7.0 - 7.5 Mohs 1.625-1.675 Tourmaline
Smoky Quartz 2.65 7.0 Mohs 1.540 - 1.550 Quartz
Spessartine 3.50 - 4.30 6.5 - 7.5 Mohs 1.790 - 1.810 Garnet
Spinel 3.58 - 4.06 8.0 Mohs 1.712 - 1.717 Spinel
Sunstone 2.55 - 2.76 6.0 - 6.5 Mohs 1.560 - 1.572 Feldspar
Topaz 3.50 - 3.60 8.0 Mohs 1.607 - 1.627 Topaz
Topazolite 3.50 - 4.30 6.5 - 7.5 Mohs 1.880 - 1.940 Garnet
Tourmaline 3.03 - 3.25 7.0 - 7.5 Mohs 1.603 - 1.655 Tourmaline
Tsavorite 3.50 - 4.30 6.5 - 7.5 Mohs 1.739 - 1.744 Garnet
Turquoise 2.60 - 2.80 5.0 - 6.0 Mohs 1.610 - 1.650 Turquoise
Uvarovite 3.50 - 4.30 6.5 - 7.5 Mohs 1.740 - 1.870 Garnet
Verdilite 3.03 - 3.25 7.0 - 7.5 Mohs 1.612-1.638 Tourmaline
Water Opal 1.98 - 2.25 5.5 - 6.5 Mohs 1.440 - 1.460 Opal
White Opal 1.98 - 2.25 5.5 - 6.5 Mohs 1.440 - 1.460 Opal
Zircon 4.60 - 4.70 7.5 Mohs 1.777 - 1.987 Zircon

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