Mohs hardness gypsum

A mineral s hardness is defined as its ability to scratch another mineral. This is usually measured using a comparative scale devised about 200 years ago by Friedrich Mohs. The Mohs scale lists ten common minerals, assigning to each a hardness from 1 (talc) to 10 (diamond). A mineral can scratch all those minerals having a lower Mohs hardness number. For example, calcite (hardness three) can scratch gypsum (hardness two) and talc (hardness one), but it cannot scratch fluorite (hardness four). 

In 1812, 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 ten specific representative materials that are arranged numerically from the softest (1) to the hardest (10). The reference minerals are (1) talc, (2) gypsum, (3) calcite, (4) fluorite, (5) apatite, (6) orthoclase feldspar, (7) quartz, (8) topaz, (9) corundum, and (10) diamond. 

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). 

Mohs hardness scale Empirical scale by which the hardness of solids can be determined by comparison with 10 reference minerals ranked from 1 to 10 1, talc 2, gypsum 3, calcite 4, fluorite 5, apatite 6, orthoclase 7, quartz 8, topaz 9, corundum and 10, diamond. 

The hardness of a mineral as measured by the Mohs scale is a criterion of its resistance to crushing [Fahrenwald, Trans. Am. In.st. Min. Metall. Pet. Eng., 112, 88 (1934)]. It is a fairly good indication of the abrasive character of the mineral, a factor that determines the wear on the grinding media. Arranged in increasing order or hardness, the Mohs scale is as fohows 1, talc 2, gypsum 3, calcite 4, fluoride 5, apatite 6, feldspar 7, quartz 8, topaz 9, corundum and 10, diamond. 

Soft and friable Sulphur, gypsum Cone crushers Ball, pebble and Ball, pebble and Moh s hardness... 

As for other physical properties, mica appeared as term 3 on a 12-term scale of hardness proposed by Breithaupt (1836). This scale was not very different from the preceding one of Mohs. Indeed, there were only two differences, namely mica between gypsum and calcite and sodalite between apatite and adularia. 

Mohs scale of hardness is a scale of scratch resistance, graduated in terms of the relative hardness of 10 common minerals, which include talc (1), gypsum (2), calcite (3), quartz (7) and diamond (10). 

In 1822, Friedrich Mohs developed a hardness scale for minerals, using ten minerals. From hardest to softest, they are diamond, corundum, topaz, quartz, potassium feldspar, apatite, fluorite, calcite, gypsum, and talc. 

Alabaster is a variety of gypsum, and is known as a decorative stone. It is white but sometimes beautifully shaded with light-colored tones of yellow or red. Its usefulness is limited by its softness (hardness 2 on Mohs scale). A gypsum curiosity is the yellow Desert rose, found in the Sahara. 

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