- Minerals are naturally occurring. They are not made by humans
- Minerals are inorganic. They have never been alive and are not made up from plants or animals
- Minerals are solids. They are not liquids (like water), or gases (like the air around you)
- Minerals have a definite chemical composition. Each one is made of a particular mix of chemical elements
- Minerals have an ordered atomic arrangement. The chemical elements that make up each mineral are arranged in a particular way – this is why minerals ‘grow’ as crystals.
There are about 4000 exceptional minerals, and every of these minerals has a completely unique set of bodily houses. These include: colour, streak, hardness, luster, diaphaneity, specific gravity, cleavage, fracture, magnetism, solubility, and lots of greater. These bodily properties are beneficial for figuring out minerals. However, they’re lots more vital in determining the capability commercial uses of the mineral. Let’s remember a few examples.
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Physical Properties of Minerals
The extent to which they absorb selectively (or transmit) certain wavelengths of visible light (“transparency versus opacity” and colour from selective wavelength absorption/transmission), the way they reflect light (“luster”) , the degree to which they slow down (and bend) any light they transmit (refraction), and the degree to which these phenomena depend on the direction in which the light travels through their atomic pattern (anisotropy of optical properties that can give rise to double refraction and dichroism).
If you use plane-polarized light, and polarizing films, you can also observe more subtle effects due to the fact that most minerals change the plane of polarization of light travelling through them in certain directions.There are other optical phenomena such as iridescence (play of colours) and asterism that are due to inhomogeneities in composition or the presence of inclusions of other minerals in a specimen.
About Optical Properties of Minerals
Classification of Minerals
Since the middle of the 19th century, minerals have been classified according to their chemical composition. Under this scheme, the dominant anions or anionic groups (eg, halides, oxides and sulfides) are classified into classes. Some reasons justify the use of this criterion as the distinguishing factor at the highest mineral classification level. First, the similarities in the properties of the minerals with the same anionic groups are generally more pronounced than those with the same dominant cation. For example, carbonates show stronger similarities to each other than copper minerals. Secondly, minerals with the same dominant anions are likely to be present in the same or similar geological environments. Therefore, while sulphates tend to occur together in vein or replacement deposits, silicate rocks form most of the Earth’s crust. Third, a nomenclature and classification scheme is used for inorganic compounds based on similar principles in current chemical practice.
However, researchers have found that the chemical composition alone is insufficient in the classification of minerals. Determination of the internal structures obtained by using X-rays provides better evaluation of the nature of minerals. The chemical composition and the internal structure together form the essence of a mineral and determine its physical properties; therefore, the classification should be based on both. Crystallochemical principles – namely those related to both the chemical composition and the crystal structure – were first applied by the British physicist W. Lawrence Bragg and the Norwegian mineralogist Victor Moritz Goldschmidt in the study of silicate minerals. The silicate group is partially cleaved on the basis of the composition, but mainly by the internal structure. Based on the topology of the SiO 4 tetrahedrons, the subclasses include framework, chain and layer silicates among others. Such mineral classifications are logical and well defined.
Native Elements is the class of the natural elements. Most minerals are made of mixtures of chemical factors. In this institution a single element just like the copper proven right here are determined in a naturally natural form.
Silicates are the most important organization of minerals. Silicates are crafted from metals blended with silicon and oxygen. There are greater silicates than all other minerals put together.The mica at the left is a member of this group.
Nesosilicates or orthosilicates, have the orthosilicate ion, which represent isolated (insular) [SiO4]four− tetrahedra which might be related best via interstitial cations. Nickel–Strunz classification.The mantle is a thick shell among the core and the crust.
Sorosilicates, They have isolated double tetrahedra groups with (Si2O7)6− or a ratio of 2:7. Nickel–Strunz classification: 09.B
Cyclosilicates: Cyclosilicates or ring silicates, have linked tetrahedra with (TxO3x)2x− or a ratio of 1:3. These exist as 3-member (T3O9)6− and 6-member (T6O18)12− rings, where T stands for a tetrahedrally coordinated cation. Nickel–Strunz classification: 09.C
Inosilicates: They are two types of inosilicates mineral.
- Single chain inosilicates: Pyroxene group ,Pyroxenoid group
- Double chain inosilicates: Amphibole group
Inosilicates or chain silicates, have interlocking chains of silicate tetrahedra with either SiO3, 1:3 ratio, for single chains or Si4O11, 4:11 ratio, for double chains. Nickel–Strunz classification: 09.D
Phyllosilicates: Phyllosilicates or sheet silicates, form parallel sheets of silicate tetrahedra with Si2O5 or a 2:5 ratio. Nickel–Strunz classification: 09.E. All phyllosilicate minerals are hydrated, with either water or hydroxyl groups attached.
Tectosilicates: Tectosilicates, or “framework silicates,” have a three-dimensional framework of silicate tetrahedra with SiO2 or a 1:2 ratio. This group comprises nearly 75% of the crust of the Earth. Tectosilicates, with the exception of the quartz group, are aluminosilicates. Nickel–Strunz classification: 09.F and 09.G, 04.DA (Quartz/ silica family)
Oxides from the combination of a steel with oxygen. This group ranges from dull ores like bauxite to gem stones like rubies and sapphires. The magnetite pictured to the left is a member of this institution.
Sulfides are manufactured from compounds of sulfur usually with a metal. They tend to be heavy and brittle. Several crucial metal ores come from this organization like the pyrite pictured here that is an iron ore.
Slufates are made of compounds of sulfur combined with metals and oxygen. It is a massive organization of minerals that have a tendency to be smooth, and translucent like this barite.
The phosphate minerals are characterized by way of the tetrahedral [PO4]three− unit, despite the fact that the structure can be generalized, and phosphorus is replaced by means of antimony, arsenic, or vanadium. The most common phosphate is the apatite group; not unusual species inside this organization are fluorapatite (Ca5(PO4)3F), chlorapatite (Ca5(PO4)3Cl) and hydroxylapatite (Ca5(PO4)3(OH)). Minerals on this group are the primary crystalline components of teeth and bones in vertebrates.
Halides from halogen elements like chlorine, bromine, fluorine, and iodine blended with steel elements. They are very smooth and without difficulty dissolved in water. Halite is a widely recognized instance of this institution. Its chemical system is NaCl or sodium chloride commonly referred to as desk salt.
Carbonates are a set of minerals made of carbon, oxygen, and a metal element. This calcite referred to as calcium carbonate is the maximum common of the carbonate group.
Mineraloid is the time period used for the ones materials that don’t match smartly into the sort of eight training. Opal, jet, amber, and mother of pearl all belong to the mineraloids.