General Information
Mohs Scale of Hardness
Mohs' hardness scale provides an index and relative measure of mineral hardness (i.e., resistance to abrasion). German geologist Frierich Mohs (1773–1839) devised a scale with specimen minerals that offered comparison of "hardness" qualities that allows the assignment of a Mohs hardness number to a mineral. Mohs' scale utilizes 10 specific representative materials that are arranged numerically from the softest (1) to the hardest (10).

The softest mineral, talc, can be used in body powder. The hardest, diamond, is used in drill bits to cut through the most dense crustal materials. Mohs' scale is a relative index scale, meaning that a determination of Mohs'hardness number for a mineral is based upon scratch tests. For example, gypsum (Mohs' hardness number 2) will scratch talc (Mohs' hardness number 1). Talc, however, will not scratch gypsum. Glass is assigned a Mohs hardness number of 5.5 because it will scratch apatite (Mohs' hardness number 5) but will not scratch orthoclase feldspar (Mohs' hardness number 6)

In order to use this scale, it is necessary to have on hand some of the minerals in the scale. If you wish to test an unknown mineral for hardness you might want to start with an ordinary specimen of apatite to see if the unknown mineral can scratch it. If the unknown mineral scratches the apatite, then you can conclude that it has a hardness of 5 or more. If the apatite can scratch the unknown mineral, then the unknown mineral has a hardness of 5 or less. If they can scratch each other, then the unknown mineral has a hardness of 5. You will need to perform other tests to narrow down the hardness. If it is softer than apatite, try calcite, etc., etc until you have narrowed down the approximate hardness. Remember, this is a relative scale and a mineral that can scratch a mineral that has a hardness of 4.5 may be given a hardness of 5, but it still might be softer than apatite.

Abrasive
An abrasive is a material, often a mineral, that is used to shape or finish a workpiece through rubbing which leads to part of the workpiece being worn away. While finishing a material often means polishing it to gain a smooth, reflective surface it can also involve roughening as in satin, matte or beaded finishes.

Abrasives are extremely commonplace and are used very extensively in a wide variety of industrial, domestic, and technological applications. This gives rise to a large variation in the physical and chemical composition of abrasives as well as the shape of the abrasive. Common uses for abrasives include grinding, polishing, buffing, honing, cutting, drilling, sharpening, and sanding

Typically, materials used as abrasives are either hard minerals (rated at 7 or above on Mohs scale of mineral hardness) or are synthetic stones, some of which may be chemically and physically identical to naturally occurring minerals but which cannot be called minerals as they did not arise naturally. (While useful for comparative purposes, the Mohs scale is of limited value to materials engineers as it is an arbitrary, ordinal, irregular scale.) Diamond, a common abrasive, for instance occurs both naturally and is industrially produced , as is corundum which occurs naturally but which is nowadays more commonly manufactured from bauxite.[1] However, even softer minerals like calcium carbonate are used as abrasives, such as "polishing agents" in toothpaste.

Abrasive minerals
Abrasives may be classified as either natural or synthetic. When discussing sharpening stones, natural stones have long been considered superior but advances in material technology are seeing this distinction become less distinct. Many synthetic abrasives are effectively identical to a natural mineral, differing only in that the synthetic mineral has been manufactured rather than been mined. Impurities in the natural mineral may make it less effective.

Some abrasive minerals (such as zirconia alumina) occur naturally but are sufficiently rare or sufficiently more difficult/costly to obtain such that a synthetic stone is used industrially. These and other artificial abrasives include:
• Borazon (cubic boron nitride or CBN)
• Ceramic
• Corundum (alumina or aluminium oxide)
• Dry ice
• Glass powder
• Silicon carbide (carborundum)
• Zirconia alumina

Abrasive minerals

	Hardness Mineral Classification   .
	10 Diamond   9 Sapphire, Ruby, Corundum   7.5-8 Beryl, Topaz, Aquamarine, Zircon, Tourline   6.5-7 Olivine (Peridot), Jade, Spodumene (Kunzite), Epidote, Cassiterite, Quartz, Garnet   6-6.5 Iron Pyrite, Rutile, Albite, Prehnite, Benitoite, Epidote, Cassiterite   5.5-6 Turquoise, Hematite, Augite, Diopside, Moldavite, Feldspar, Titanium HARD 5-5.5 Goethite, Natrolite, Datolite, Analcime, Wollastonite, Apatite   4.5-5 Apophyllite, Scheelite   4-4.5 Platinum, Smithsonite, Wolframite, Fluorite   3.5-4 Aragonite, Ankerite, Dolomite, Azurite, Malachite, Sphalerite, Chalcopyrite, Cuprite, Rhodochrosite, Strontianite, Stilbite, Heulandite, Mimetite   3-3.5 Barite, Celestite, Cerussite, Atacamite   3 Wulfenite, Vanadinite, Bornite, Calaite MEDIUM 2.5-3 Gold, Silver, Copper, Galena, Anglesite, Mica Phlogopite, Aluminium   2.5 Micas (Biotite,Lepidolite)   2-2.5 Cinnabar, Amber, Mica Muscovite   2 Sulfur, Gysum   1.5-2 Molybdenite   1-2 Aurichalcite, Talc SOFT

To add more values to the mineral, Pands Group expertly provides the dressing services, comprised of crushing, screening, floatation, grinding, and air separator. Many local and international top enterprises, especially in the oil industry, have confidence in our products and always choose us to be their main supplier. Pands Group is an expertise in grinding ores of 1 to 7 on the Mohs scale, including with barites, dolomite, limestone, silica sand, quartz, feldspar, calcite, gypsum, graphite, fluorite, coal, gangue, granite, phosphate ore, manganese metal, ferromanganese, slag, orthoclase, marble, potash, iron ore, etc.

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