Monthly archives: July, 2021

Copper minerals

Copper minerals are a group of minerals, which contain the copper element in their chemical composition. Here are some important copper minerals; (1). Azurite: Cu3(CO3)2(OH)2 Physical Properties: Crystal System: monoclinic Cleavage: Perfect prismatic cleavage Hardness: 3.5 – 4. Specific Gravity: 3.77 Lustre: Vitreous Colour: Azure-blue Streak: pale-blue Habit: Crystalline. Also in radiating groups or massive. …

Manganese Minerals

(1). Braunite: Mn2+Mn3+6[O8|SiO4] Braunite is a silicate mineral, which contains both di- and tri-valent manganese. Common impurities include iron, calcium, boron, barium, titanium, aluminium, and magnesium. Physical Properties of Braunite: Crystal System: Hexagonal Cleavage: Braunite has no cleavage Fracture: Uneaven Hardness: 6 – 6.5 on Moh’s scale Sp.Gr: 4.75 – 4.82 Lustre: submetallic lustre Colour: …

Iron Minerals

(1). Magnetite: Fe3O4 Physical properties of Magnetite: Crystal System: cubic Cleavage: Absent Hardness: 6 in Moh’s scale Sp.Gr: 5.18 Lustre: metallic to dull Colour: Iron Black Special Character: Strongly magnetic. A natural magnet is called ”Iodestone”. Habit: Octahedral crystals, massive or granular. Occurrence of Magnetite: Magnetite is a high-temperature mineral, which occurs as an accessory …

Alluminium Minerals

The minerals which contain aluminium element are known as the Aluminium Minerals. Some of the important aluminium minerals are as under: (1). Bauxite: Al2O3 Bauxite is a mixture of hydrous aluminium oxides. The physical properties of Bauxite are as under; Physical Properties: Crystal System: Bauxite is a mixture of several minerals such as gibbsite,diaspore, and …

Calcium Minerals

Calcium Minerals: Calcium minerals are those minerals, which, somehow, contains calcium in their chemical composition. Some of the calcium minerals are as under: (1). Calcite: CaCo3 Physical properties:  Crystal System: Hexagonal Cleavage: Calcite has perfect cleavage. Hardness: Calcite is a soft mineral, which has a hardness of 2 at Moh’s scale. Specific Gravity: The specific …

Al2SiO5 (Polymorphs) minerals

Al2SiO5/Polymorphs Group of Minerals: The three important minerals of this group are ; Andalusite Sillimanite Kyanite These minerals occur in metamorphosed luminous rocks, such as pelitic schists. (1). Andalusite (Al2SiO5): Physical properties of Andalusite: Crystal System: Andalusite occurs in orthorhombic crystal form. Cleavage: Andalusite has a poor cleavage. Fracture: Uneven fracture Hardness: Andalusite has a …

Minerals of Clay Group

Clays consist mainly of a group of crystalline substances known as the ”clay minerals”. They are all essentially hydrous aluminium silicates. Well known minerals are of as under: (1). Kaolinite: Al2O3 2SiO2 Physical properties of kaolinite are as under; Crystal System: Triclinic crystal system. Cleavage: Perfect basal cleavage. Hardness: 2 at Moh’s Scale Sp.gr: Specific …

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: Red brown in colour, and has a hardness 7-7.5 on …