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Moh's Hardness Scale & Tumbling

Number 1 rule of tumbling - The batch of material should consist of same or close harness.

Sort by: Name Hardness

Actinolite  5.5 - 6.5   Calcium, iron, magnesium
Agate  7  Oxide of Silicon
Amethyst  7  Oxide of Silicon
Apatite  5  Phosphate of calcium & fluorene
Aventurine  7  Oxide of silicon
Beryl  7.5 - 8  Silicate of beryllium & aluminum
Calcite  3  Carbonate of calcium
Carnelian  7  Oxide of silicon
Chalcopyrite  3.5-4  Sulphide of copper & iron
Chrysoprase  7  Oxide of silicon & nickle oxide
Epidote  6 - 7  Orthosilicate of calcium & aluminum
Feldspar  6  Silicate of aluminum & potassium
Fluorite  4  Calcium fluoride
Galena  2.5  Sulphide of lead
Garnet  6.5 - 7.5  Silicat of iron, aluminum & calcium
Hemitite  5.5 - 6.5  Oxide of iron
Jasper  7  Oxide of silicon
Jet  2 - 2.5  Hydrocarbon
Kyanite  4 - 7  Silicate of aluminum
Lapis Lazuli  5.5 - 6  Silicate of sodium & aluminum
Lepidolite  2.5 - 4  Lithium mica
Meteorite  5  Nickelferous iron
Mica  2 -3  Orthosilicate of aluminum & potass
Obsidian  5  Volcanic glass
Opal  5.5 - 6.5  Oxide of silicon & water
Petrified Wood  7  Oxide of silicon
Pyrite  6 - 6.5  Sulphite of iron
Rock crystal  7  Oxide of silicon
Ruby  9  Oxide of aluminum
Saphire  9  Oxide of aluminum
Spodumene  6.5 - 7  Silicate of lithium & aluminum
Sulpher  1.5 - 2  Sulphur
Talc  1 - 1.5  Acid metasilicate
Tiger Eye  7  Oxide of silicon
Topaz  8  Silicate of aluminum & florine
Tourmaline  7 - 7.5  Complex silicate of boron & copper
Turquoise  5 - 6  Phosphate of aluminum & copper
1 - 1.5  Talc  Acid metasilicate
1.5 - 2  Sulpher  Sulphur
2 - 2.5  Jet  Hydrocarbon
2 -3  Mica  Orthosilicate of aluminum & potass
2.5  Galena  Sulphide of lead
2.5 - 4  Lepidolite  Lithium mica
3  Calcite  Carbonate of calcium
3.5-4  Chalcopyrite  Sulphide of copper & iron
4 - 7  Kyanite  Silicate of aluminum
4  Fluorite  Calcium fluoride
5  Apatite  Phosphate of calcium & fluorene
5  Meteorite  Nickelferous iron
5  Obsidian  Volcanic glass
5 - 6  Turquoise  Phosphate of aluminum & copper
5.5 - 6  Lapis Lazuli  Silicate of sodium & aluminum
5.5 - 6.5  Actinolite   Calcium, iron, magnesium
5.5 - 6.5  Hemitite  Oxide of iron
5.5 - 6.5  Opal  Oxide of silicon & water
6 - 6.5  Pyrite  Sulphite of iron
6 - 7  Epidote  Orthosilicate of calcium & aluminum
6  Feldspar  Silicate of aluminum & potassium
6.5 - 7  Spodumene  Silicate of lithium & aluminum
6.5 - 7.5  Garnet  Silicat of iron, aluminum & calcium
7 - 7.5  Tourmaline  Complex silicate of boron & copper
7  Agate  Oxide of Silicon
7  Amethyst  Oxide of Silicon
7  Aventurine  Oxide of silicon
7  Carnelian  Oxide of silicon
7  Chrysoprase  Oxide of silicon & nickle oxide
7  Jasper  Oxide of silicon
7  Petrified Wood  Oxide of silicon
7  Rock crystal  Oxide of silicon
7  Tiger Eye  Oxide of silicon
7.5 - 8  Beryl  Silicate of beryllium & aluminum
8  Topaz  Silicate of aluminum & florine
9  Ruby  Oxide of aluminum
9  Saphire  Oxide of aluminum


Tumble like a Pro!
Click to Download instructions from Steve

Use glass jars to store your buffing compounds. Coffee cans or tins can rust under the wet compound and pieces of rust can scratch your specimen.


Measuring An Ounce of Grit

Many Tumbling instructions tell you how much grit or polish to use per pound of rock, and this is usually in ounces. If you do not have an ounce scale handy, here are the equivilant teaspoon measurements.

Course Grit: 1oz = 4 level tsps.
Medium Grit: 1oz = 4 level tsps.
Fine Grit: 1oz = 4 level tsps.
Polish Powder: 1oz = 8 level tsps.


Thought about a Vibratory Tumbler?
Learn how to get the perfect balance of grit / water.


Tumbled Obsidian                        Tumbled Petrified Wood


More information & advice on Tumbling http://www.rocktumblinghobby.com



Last Updated:5/20/2017
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