Monthly archives: July, 2021

Miscellaneous Ores

(1). Chromite: Fe2+Cr2O4 Physical Properties of Chromite: Crystal Systems: Cubic Cleavage: Absent Fracture: uneven Hardness: 5.5 on Moh’s scale Sp.Gr: 4.6 Lustre of Chromite: Submetallic Colour: Black Streak: Dark Brown Habit: commonly massive or granular Occurrence: Chromite occurs in igneous rocks such as peridotites and other ultrabasic rocks and in serpentine derived from them. It is …

Zinc and Lead minerals

Minerals enriched with lead and zinc in their chemical composition are said to be Zinc and Lead Minerals. Some of the important minerals that contains zinc and lead are as follow: (1). Galena: PbS Physical properties of Galena: Crystal Systems: Galena is found in the cubic crystal systems. Cleavage of Galena: perfect cubic cleavage (cubic …

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 …