Common minerals : Diopside, Hedenbergite, Augite etc. Classes of the System Unit forms of Normal class : Form No. of faces Miller Indices Basal pinacoid‘c’ pinacoid 2 001 ‘a’ pinacoidFront pinacoidOrtho pinacoid 2 100 ‘b’ pinacoidSide pinacoidClino pinacoid 2 010 Prism 4 110 Hemi macrodome 02 (2) 101 Clinodome 4 011 Hemi pyramid 4 (2) […]
Rules of substitution Terminology related to partitioned between the solid & liquid phase Distribution coefficients and Geothermometers Distribution coefficient (D) = Cs/ Cl where, Cs = the concentration of a minor element in the crystal of a mineral Cl = the concentration of that element in the liquid from which the crystal formed under equilibrium
Ionic Substitution in Minerals/ Crystals Read More »
Feldspar are the most common rock forming minerals of the Earth’s crust Structure Classification Physical Properties Optical Properties Under PPL Under XPL Varities : Some advanced material Occurrance : Uses of feldspar :
Amphiboles are the common constituents in both Igneous and Metamorphic rocks. General formula of Amphiboles is , W0-1X2Y5(Z8O22)(OH,F)2 Structure Amphiboles Classification Orthorhombic amphiboles Triclinic amphiboles Monoclinic amphiboles General Physical and Optical properties Physical Properties Optical properties
The crystallographic axes are the imaginary lines that we can draw within the crystal lattice. These crystal axis than works as the coordinate system within the crystal. These are well defined lines for the crystals. “On the basis of number of crystal axes and mutual relationship between them we define a crystal system“ Crystal system
Crystal System and Their Identification Read More »
There are three elements of crystal forms. The face, edge and solid angle. Forms – It is a group of faces which have a like positions with respect to the crystallographic orientations. Forms may be classified in the following three ways – 1st way 2nd way 3rd way Simple form – when a crystal is
The carbonate mineral group form in the environment where water and carbon-di-oxide are present. The (CO3)– complex are basic building units of all carbonate minerals and are responsible for the properties to group. An acid test is widely used for identification of carbonates. Calcite Group (Hexagonal) Dolomite Group (Hexagonal) Aragonite Group (Orthorhombic) Calcite [CaCO3]Magnesite [MgCO3]Siderite
Garnets is a group of 6 members that are crystallizes in the cubic system with a profound rhobdodecahedral cleavage. Structure Physical and Optical Properties Physical propoerties Optical properties Varities – There are many varities of the Garnet minerals – Occurance –
The mica group of minerals crystallizes in the monoclinic system. They are phyllosilicates with their general formula as – X2Y4-6Z8O20[OH,F]4 Where, X = K, Na, Ba, Ca Y = Al, Mg, Fe+2, Li, Cr, Mn, Zn Z = Si, Al, Fe+3 STRUCTURE physical and optical properties physical properties optical properties Mode of occurrence –
Pyroxenes are formed either direct or by the reaction of olivine with quartz. Structure Important minerals – Optical Properties Orthopyroxene Clinopyroxene Alteration – Orthopyroxene alter to serpentine or fibrous amphibole. Augite alters to chlorite/ hornblende. Varities – Occurances – REFERENCES –
