"77 AD. While greatly facilitating the identification of minerals in the field, the Mohs scale does not show how well hard materials perform in an industrial setting. Despite its lack of precision, the Mohs scale is highly relevant for field geologists, who use the scale to roughly identify minerals using scratch kits. The Mohs scale hardness of minerals can be commonly found in reference sheets. Mohs hardness is useful in milling. It allows assessment of which kind of mill will best reduce a given product whose hardness is known. The scale is also in use at digital electronic manufacturers, for"
"Mohs scale of mineral hardness The Mohs scale of mineral hardness is a qualitative ordinal scale characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material. Created in 1812 by German geologist and mineralogist Friedrich Mohs, it is one of several definitions of hardness in materials science, some of which are more quantitative. The method of comparing hardness by seeing which minerals can visibly scratch others is, however, of great antiquity, having been mentioned by Theophrastus in his treatise ""On Stones"", c. 300 BC, followed by Pliny the Elder in his ""Naturalis Historia"", c."
"incorporates additional substances that may fall between levels: Comparison between hardness (Mohs) and hardness (Vickers): Mohs scale of mineral hardness The Mohs scale of mineral hardness is a qualitative ordinal scale characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material. Created in 1812 by German geologist and mineralogist Friedrich Mohs, it is one of several definitions of hardness in materials science, some of which are more quantitative. The method of comparing hardness by seeing which minerals can visibly scratch others is, however, of great antiquity, having been mentioned by Theophrastus in his treatise"
"Mercalli intensity scale The Mercalli intensity scale is a seismic intensity scale used for measuring the intensity of an earthquake. It measures the ""effects"" of an earthquake. It is distinct from the moment magnitude (""M"") usually reported for an earthquake, which is a measure of the ""energy"" released (sometimes misreported as the Richter magnitude, ""M""). The intensity of an earthquake is not entirely determined by its magnitude. It is not based on first physical principles, but is, instead, empirically based on observed effects. The Mercalli scale quantifies the effects of an earthquake on the Earth's surface, humans, objects of nature,"
"necessarily constant for all sides, which is a function of its structure; crystallographic weakness renders some directions softer than others. An example of this property exists in kyanite, which has a Mohs hardness of 5½ parallel to [001] but 7 parallel to [100]. The most common scale of measurement is the ordinal Mohs hardness scale. Defined by ten indicators, a mineral with a higher index scratches those below it. The scale ranges from talc, a phyllosilicate, to diamond, a carbon polymorph that is the hardest natural material. The scale is provided below: Lustre indicates how light reflects from the mineral's"
"Moment magnitude scale The moment magnitude scale (MMS; denoted as M"" or M"") is one of many seismic magnitude scales used to measure the size of earthquakes. The scale was developed in the 1970s to succeed the 1930s-era Richter magnitude scale (""M""). Even though the formulas are different, the new scale was designed to produce magnitude values for a given earthquake similar to those produced by the older one. Under suitable assumptions, as with the Richter magnitude scale, an increase of one step on this logarithmic scale corresponds to a 10 (about 32) times increase in the amount of energy"
"Friedrich Mohs Carl Friedrich Christian Mohs (; 29 January 1773 – 29 September 1839) was a German geologist and mineralogist. He was the creator of the Mohs scale of mineral hardness. Mohs was born in Gernrode, Germany. Mohs studied chemistry, mathematics and physics at the University of Halle and also studied at the Mining Academy in Freiberg, Saxony. After assuming the position of a foreman at a mine in 1801, Mohs moved in 1802 to Austria, where he was employed in trying to identify the minerals in a private collection of a banker. In 1812 he moved to Graz where"
"test is Mohs scale, which is used in mineralogy. One tool to make this measurement is the sclerometer. Another tool used to make these tests is the pocket hardness tester. This tool consists of a scale arm with graduated markings attached to a four-wheeled carriage. A scratch tool with a sharp rim is mounted at a predetermined angle to the testing surface. In order to use it a weight of known mass is added to the scale arm at one of the graduated markings, the tool is then drawn across the test surface. The use of the weight and markings"
"testing the resilience of certain flat panel display components (such as cover glass for LCDs or encapsulation for OLEDs). The Mohs scale of mineral hardness is based on the ability of one natural sample of mineral to scratch another mineral visibly. The samples of matter used by Mohs are all different minerals. Minerals are chemically pure solids found in nature. Rocks are made up of one or more minerals. As the hardest known naturally occurring substance when the scale was designed, diamonds are at the top of the scale. The hardness of a material is measured against the scale by"
"isolated area. Several scales have historically been described as the ""Richter scale"", especially the ""local magnitude"" formula_2 and the surface wave formula_3 scale. In addition, the ""body wave magnitude"", formula_4, and the ""moment magnitude"", formula_5, abbreviated MMS, have been widely used for decades. A couple of new techniques to measure magnitude are in the development stage by seismologists. All magnitude scales have been designed to give numerically similar results. This goal has been achieved well for formula_2, formula_3, and formula_5. The formula_4 scale gives somewhat different values than the other scales. The reason for so many different ways to measure"
"pressure"" (damage threshold) than an absolute scale. Absolute scales are typically used in science, deep vacuum measurements (where the fluctuating pressure of the atmosphere becomes a nuisance), aeronautics (where precise measurements of the atmosphere are needed to determine altitude), or lighting construction (where the relative pressure of the atmosphere is inconsequential), and are measured in units of ""atmospheres"" or torr. Barometers do measure absolute pressure by holding a vacuum at the top of the mercury column or one side of a diaphragm, but that vacuum is awkward to achieve and maintain. Thus, while the general public may be familiar with"
"integrity, they are not considered ""scratches"" for the determination of a Mohs scale number. The Mohs scale is a purely ordinal scale. For example, corundum (9) is twice as hard as topaz (8), but diamond (10) is four times as hard as corundum. The table below shows the comparison with the absolute hardness measured by a sclerometer, with pictorial examples. On the Mohs scale, a streak plate (unglazed porcelain) has a hardness of approximately 7.0. Using these ordinary materials of known hardness can be a simple way to approximate the position of a mineral on the scale. The table below"
"measure the mass, force exertion, tension and resistance of an object without the need of a power supply. Types of mechanical scale include spring scales, hanging scales, triple beam balances and force gauges. A spring scale measures mass by reporting the distance that a spring deflects under a load. This contrasts to a ""balance"", which compares the torque on the arm due to a sample weight to the torque on the arm due to a standard reference mass using a horizontal lever. Spring scales measure force, which is the tension force of constraint acting on an object, opposing the local"
"indirectly and incompletely reflect the force of an earthquake, involve other factors, and are generally limited in some respect of magnitude, focal depth, or distance. The ""moment magnitude scale"" – Mw or M – developed by and , is based on an earthquake's ""seismic moment"", M, a measure of how much work an earthquake does in sliding one patch of rock past another patch of rock. Seismic moment is measured in Newton-meters (Nm or Nm) in the SI system of measurement, or dyne-centimeters (dyn-cm) in the older CGS system. In the simplest case the moment can be calculated knowing only"
"professor in Graz. In 1826, Mohs was a Professor in Vienna. In 1816, Mohs settled in Vienna. In 1818, Mohs moved to Freiberg, Saxony. Mohs died during a trip to Agordo, Italy in 1839, at the age of 66. Friedrich Mohs Carl Friedrich Christian Mohs (; 29 January 1773 – 29 September 1839) was a German geologist and mineralogist. He was the creator of the Mohs scale of mineral hardness. Mohs was born in Gernrode, Germany. Mohs studied chemistry, mathematics and physics at the University of Halle and also studied at the Mining Academy in Freiberg, Saxony. After assuming the"
"Mohs scale, depending on the type of alloy, heat treatment, and whether it is case-hardened or not. An examination of several Klerksdorp spheres found none to be harder than 5.0 on the Mohs scale. For comparison, common glass has a Mohs hardness of 5.5. Klerksdorp sphere Klerksdorp spheres are small objects, often spherical to disc-shaped, that have been collected by miners and rockhounds from 3-billion-year-old pyrophyllite deposits mined by Wonderstone Ltd., near Ottosdal, South Africa. They have been cited by some alternative researchers and reporters in books, popular articles, and many web pages, as inexplicable out-of-place artifacts that could only"
"have a hardness that depends significantly on direction. Hardness can also be measured on an absolute scale using a sclerometer; compared to the absolute scale, the Mohs scale is nonlinear. ""Tenacity"" refers to the way a mineral behaves when it is broken, crushed, bent or torn. A mineral can be brittle, malleable, sectile, ductile, flexible or elastic. An important influence on tenacity is the type of chemical bond (""e.g.,"" ionic or metallic). Of the other measures of mechanical cohesion, ""cleavage"" is the tendency to break along certain crystallographic planes. It is described by the quality (""e.g."", perfect or fair) and"
"Mel scale The mel scale, named by Stevens, Volkmann, and Newman in 1937, is a perceptual scale of pitches judged by listeners to be equal in distance from one another. The reference point between this scale and normal frequency measurement is defined by assigning a perceptual pitch of 1000 mels to a 1000 Hz tone, 40 dB above the listener's threshold. Above about 500 Hz, increasingly large intervals are judged by listeners to produce equal pitch increments. As a result, four octaves on the hertz scale above 500 Hz are judged to comprise about two octaves on the mel scale."
"Mohr's circle Mohr's circle, named after Christian Otto Mohr, is a two-dimensional graphical representation of the transformation law for the Cauchy stress tensor. After performing a stress analysis on a material body assumed as a continuum, the components of the Cauchy stress tensor at a particular material point are known with respect to a coordinate system. The Mohr circle is then used to determine graphically the stress components acting on a rotated coordinate system, i.e., acting on a differently oriented plane passing through that point. The abscissa, formula_1, and ordinate, formula_2, of each point on the circle, are the magnitudes"
"refractometer actually measures the refractive index of the grape must, it can be translated to many different scales (both related and unrelated to wine) based on their correlation to refractive index. Thus, all of these methods are similar and the differences are more cultural than significant, but all are equally valid ways to measure the density of grape must and other sugar-based liquids. The Normalizovaný Moštomer (°NM) measures kg of sugar in 100 l of must and is used in Czech Republic and Slovakia. Oechsle scale The Oechsle Scale is a hydrometer scale measuring the density of grape must, which"
"finding the hardest material that the given material can scratch, or the softest material that can scratch the given material. For example, if some material is scratched by apatite but not by fluorite, its hardness on the Mohs scale would fall between 4 and 5. ""Scratching"" a material for the purposes of the Mohs scale means creating non-elastic dislocations visible to the naked eye. Frequently, materials that are lower on the Mohs scale can create microscopic, non-elastic dislocations on materials that have a higher Mohs number. While these microscopic dislocations are permanent and sometimes detrimental to the harder material's structural"
"The inner scale represents sensible-total heat ratio (SHF). The outer scale gives the ratio of enthalpy difference to humidity difference. This is used to establish the slope of a condition line between two processes. The horizontal component of the condition line is the change in sensible heat while the vertical component is the change in latent heat. Psychrometric charts are available in SI (metric) and IP (U.S./Imperial) units. They are also available in low and high temperature ranges and for different pressures. The ""Mollier ""i""-""x"""" (Enthalpy - Humidity Mixing Ratio) diagram, developed by Richard Mollier in 1923, is an alternative"
"Scale height In various scientific contexts, a scale height is a distance over which a quantity decreases by a factor of ""e"" (approximately 2.72, the base of natural logarithms). It is usually denoted by the capital letter ""H"". For planetary atmospheres, scale height is the increase in altitude for which the atmospheric pressure decreases by a factor of ""e"". The scale height remains constant for a particular temperature. It can be calculated by or equivalently where: The pressure (force per unit area) at a given altitude is a result of the weight of the overlying atmosphere. If at a height"
"strength, also measured in amperes per meter. Susceptibility is a dimensionless quantity. For chemical applications the molar magnetic susceptibility (χ) is the preferred quantity. It is measured in m·mol (SI) or cm·mol (CGS) and is defined as where ρ is the density in kg·m (SI) or g·cm (CGS) and ""M"" is molar mass in kg·mol (SI) or g·mol (CGS). A variety of methods are available for the measurement of magnetic susceptibility. When an isolated atom is placed in a magnetic field there is an interaction because each electron in the atom behaves like a magnet, that is, the electron has"
"metres, ""n"" is measured in moles, and ""T"" in kelvins (the Kelvin scale is a shifted Celsius scale, where 0.00 K = −273.15 °C, the lowest possible temperature). ""R"" has the value 8.314 J/(K·mol) ≈ 2 cal/(K·mol), or 0.08206 L·atm/(mol·K). How much gas is present could be specified by giving the mass instead of the chemical amount of gas. Therefore, an alternative form of the ideal gas law may be useful. The chemical amount (""n"") (in moles) is equal to total mass of the gas (""m"") (in grams) divided by the molar mass (""M"") (in grams per mole): By replacing"
"the International Association of Seismology and Physics of the Earth's Interior (IASPEI) has standardized the measurement procedures and equations for the principal magnitude scales, , , , and . The first scale for measuring earthquake magnitudes, developed in 1935 by Charles F. Richter and popularly known as the ""Richter"" scale, is actually the , label ML or M. Richter established two features now common to all magnitude scales. First, the scale is logarithmic, so that each unit represents a ten-fold increase in the ""amplitude"" of the seismic waves. As the energy of a wave is 10 times its amplitude, each"
"is often measured in torrs, named for Torricelli, an early Italian physicist (1608–1647). A torr is equal to the displacement of a millimeter of mercury (mmHg) in a manometer with 1 torr equaling 133.3223684 pascals above absolute zero pressure. Vacuum is often also measured on the barometric scale or as a percentage of atmospheric pressure in bars or atmospheres. Low vacuum is often measured in millimeters of mercury (mmHg) or pascals (Pa) below standard atmospheric pressure. ""Below atmospheric"" means that the absolute pressure is equal to the current atmospheric pressure. In other words, most low vacuum gauges that read, for"
"kind of measurement is called cryoscopy (Greek ""cryo"" = cold, ""scopos"" = observe; ""observe the cold"") and relies on exact measurement of the freezing point. The degree of dissociation is measured by determining the van 't Hoff factor ""i"" by first determining ""m"" and then comparing it to ""m"". In this case, the molar mass of the solute must be known. The molar mass of a solute is determined by comparing ""m"" with the amount of solute dissolved. In this case, ""i"" must be known, and the procedure is primarily useful for organic compounds using a nonpolar solvent. Cryoscopy is"
"Oechsle scale The Oechsle Scale is a hydrometer scale measuring the density of grape must, which is an indication of grape ripeness and sugar content used in wine-making. It is named for Ferdinand Oechsle (1774-1852) and it is widely used in the German, Swiss and Luxembourgish wine-making industries. On the Oechsle scale, one degree Oechsle (° Oe) corresponds to one gram of the difference between the mass of one litre of must at 20 °C and 1 kg (the mass of 1 litre of water). For example, must with a specific mass of 1084 grams per litre has 84° Oe."
"both scales. Unlike other scales, the moment magnitude scale does not saturate at the upper end; there is no upper limit to the possible measurable magnitudes. However, this has the side-effect that the scales diverge for smaller earthquakes. Various ways of determining moment magnitude have been developed, and several subtypes of the scale can be used to indicate the basis used. Moment magnitude scale The moment magnitude scale (MMS; denoted as M"" or M"") is one of many seismic magnitude scales used to measure the size of earthquakes. The scale was developed in the 1970s to succeed the 1930s-era Richter"
"German geophysicist August Heinrich Sieberg and became known as the Mercalli–Cancani–Sieberg (MCS) scale. The Mercalli–Cancani–Sieberg scale was later modified by Harry O. Wood and Frank Neumann, and published in English in 1931 as the Mercalli–Wood–Neumann (MWN) scale. It was later improved by Charles Richter, the father of the Richter magnitude scale. The scale is known today as the Modified Mercalli scale (MM) or Modified Mercalli Intensity scale (MMI). The lower degrees of the Modified Mercalli Intensity scale generally deal with the manner in which the earthquake is felt by people. The higher numbers of the scale are based on observed"
"Mud balance A mud balance, also known as a mud scale is a device used to measure the density (weight) of drilling fluid, cement or any type of liquid or slurry. It consists of a graduated beam with a bubble level and a weight slider along its length and a cup with a lid on one end. The cup is used to hold a fixed amount of fluid so it can be weighed. A slider-weight can be moved along the beam, and a bubble indicates when the beam is level. Density is read at the point where the slider-weight sits"
"classified into density (often given as specific gravity); measures of mechanical cohesion (hardness, tenacity, cleavage, fracture, parting); macroscopic visual properties (luster, color, streak, luminescence, diaphaneity); magnetic and electric properties; radioactivity and solubility in hydrogen chloride (). ""Hardness"" is determined by comparison with other minerals. In the Mohs scale, a standard set of minerals are numbered in order of increasing hardness from 1 (talc) to 10 (diamond). A harder mineral will scratch a softer, so an unknown mineral can be placed in this scale by which minerals it scratches and which scratch it. A few minerals such as calcite and kyanite"