Minerals of Serpentine Group

The word serpentine has been derived from ”Serpent”, which means greenish. Serpentines are so called because of their green colors. Serpentine occurs in two distinct forms: (i) ”Antigorite”; a platy variety, and (ii) ”Chrysolite; a fibrous variety. Minerals species of Serpentine Group: Amesite: Chemical composition of Amesite is Mg2Al2SiO5(OH)4., however if an Amesite has Ni …

Chlorite group of minerals

The chlorite group includes a number of minerals, which have similar physical properties. They are sheet silicate (phyllosilicate) minerals, which were formed during early metamorphism. They have an oily/soapy feel and perfect cleavage. They are found in all sedimentary, igneous, and metamorphic rocks. The important mineral of this group is ”Chlorite”. Chlorite Minerals: (Mg,Fe) 3(Si,Al) …

Minerals of Garnet Group

The garnets comprise a group of isomorphous minerals with the general formula X3Y2(SiO4), where X may be Ca, Mg, Mn, or Fe+2 and Y may be Al, Cr3+. The common garnets are: Pyrope: Al2Mg3O12Si3: Red to Purple with a hardness 7-7.5 on Moh’s scale. Almandine: Fe++3Al2(SiO4)3:┬áRed brown in colour, and has a hardness 7-7.5 on …

Olivine Group of Minerals

In the earlier article we have discussed different groups of minerals, like Mica, Amphibole, Pyroxene, Quartz group of minerals. This is another important group of minerals, which include a series of minerals that crystallize in the orthorhombic system. These minerals range in composition from ”forsterite” Mg2 SiO4. The composition of common Olivine is (Mg,Fe)2 SiO4. …

Minerals of Mica Group

Mica is a group of transparent to translucent minerals, the members of which have similar chemical and physical properties. Mica is a member of Silicate minerals. These minerals are known as Micas. Micas are general found in thin slidal layers, which is why these are also known as ”Sheet Minerals”. There are more than thirty …

Amphibole group of minerals

The amphibole group includes a number of minerals, which have a closely related structure and chemical composition. The amphiboles contain hydroxyl group in the structure. The angle between two sets of cleavages is 124┬░ and is characteristic of amphiboles. “Trimolite” (hydrous silicate of Ca and Mg), ”actinolite” (hydrous silicate of Ca, Mg, and Fe), and …

Minerals of pyroxene group

Pyroxene forms an important group of rock minerals. They have a general formula XYSi2O6, where X is diavalent caution mainly Ca, Fe, Mg, while Y is monovalent cation like Na, Li and Trivalent caution Al, Fe. In some cases, Al may partly replace silicon. The common pyroxenes are Ca, Mg, and Fe silicates. They are …

Quartz; The minerals of Silica Group

Quartz is the collective name used for the minerals of Silica group. The Chemical composition of all minerals of quartz is Silicon and Oxygen. The chemical formula of these minerals is SiO2. Quartz is commonly found in vugs or pockets in pegmatite dikes (coarse-grained igneous rocks). There are more than 30 types of quartz, among …

Sodalite Mineral

Sodalite: White, Green and grey colors of Sodlite mineral Sodalite is the third major mineral of the Feldspathoid group. It is comparatively rare than Nepheline and Leucite. It is found in blue and blue-voilet colors. Its chemical composition is Na4Al3Si3O12Cl. It is included in semi-precious gemstones. Its blue color helps to diagnose it. Its physical …

Leucite Mineral

Leucite Mineral: Leucite mineral is found in grey, yellow-grey, white, and even in colorless form. Leucite is another important rock-forming mineral of the feldspathoid group which includes potassium and aluminum tectosilicate and has a chemical formula KAlSi2O6. The name leucite has been derived from the Greek leucos for white, in allusion to its color. Specimens …