Mohs Extended Scale

The Mohs scale is a system of testing the hardness of a mineral, designed by Friedrich Mohs in 1812. Mohs was a mineralogist from Germany who wanted a simple way of testing the “scratching” ability of each mineral. What the mineral could scratch, or what could scratch the mineral determines its position on the Mohs scale.

​Mohs designed the Mohs scale to work with relatively ordinary devices. For example, one tested the hardness of a mineral with things like a fingernail, a penny, glass, or a knife. Even having access to only a few of these things in the field could help determine a mineral’s placement on the Mohs scale.

​Plastic   1
Graphite   1
Talc   1
Pencil Lead   1
Sulfur   1.5 – 2.5
Gypsum   2
Alabaster   2
Rock Salts   2
Plaster of Paris   2
Mercury   2 – 2.5
Salt   2 – 3
Amber   2.5
Ivory   2.5
Fingernail   2.5
Pearl   2.5
Zinc   2.5
Gold   2.5 – 3
Silver   2.5 – 3
Aluminum   2.5 – 3
Jet   2.5 – 3
Copper Penny   3
Calcite   3
Limestone   3
Shells   3
Bronze   3
Coral   3
Barite   3 – 3.5
Malachite   3.5 – 4
Azurite   3.5 – 4
Fluorite   4
Platinum   4 – 4.5
Iron   4 – 5
Meteorite   4.5
Palladium   4.75
Apatite   5
Tooth Enamel   5

Lapis   5 – 5.5
Obsidian   5 – 5.5
Hematite   5 – 6
Knife Blade   5.5
Opal   5.5 – 6
Turquoise   5.5 – 6
Magnetite   5.5 – 6.5
Rhodonite   5.5 – 6.5
Titanium   6
Rhodium   6
Feldspar   6
Orthoclase   6
Rutile   6 – 6.5
Fire Opal   6 – 6.5
Moonstone   6 – 6.5
Marcasite   6 – 6.5
Iron Pyrite   6.5
Tanzanite   6.5
Nephrite   6 – 7
Jade   6 – 7
Glass   6 – 7
Cassiterite   6 – 7
Iridium   6.5
Kunzite   6.5 – 7
Peridot   6.5 – 7
Bloodstone   7
Quartz   7
Rose Quartz   7
Smokey Quartz   7
Milk Quartz   7
Black Opal   7
Flint   7
Aventurine   7
Ametrine   7
Agate   7
Chalcedony   7

Citrine   7
Jasper   7
Onyx   7
Carnelian   7
Amethyst   7
Tiger's Eye   7
Garnet   7 – 7.5
Rhodolite   7 – 7.5
Iolite   7 – 7.5
Tourmaline   7 – 7.5
Steel File   7 – 8
Zircon   7.5
Tungsten   7.5
Morganite   7 – 8
Beryl   7.5 – 8
Aquamarine   7.5 – 8
Emerald   7.5 – 8
Spinel   8
Topaz   8
Smokey Topaz   8
Blue Topaz   8
Yellow Topaz   8
Chrysoberyl   8.5
Alexandrite   8.5
Cat's Eye   8.5
Cubic Zirconia   8.5
Chromium   8.5
Tungsten Carbide   8.5 – 9
Corundum   9
Sapphire   9
Ruby   9
Carborundum   9 – 9.5
Moissanite   9.25
Fullerite   10-
Diamond   10
Nanorods   10+