Stone
Sources of Stones
Main sources of stones are rocks. Rocks are not homogeneous they are having indefinite shape and chemical compositions. They are available at the earth's crust. They are mainly of two kind.
Monomineralic and Polymineralic.
The rocks which contain only one mineral are specified as monomineralic rocks.
Examples : Quartz, Pure Gypsum and Magnesite
The rocks which contain two or more than two minerals are specified as polymineralic rocks.
Example : Basalt and Granite
What is Mineral ?
Minerals are the substance which contains specific chemical composition in it and molecular structure. This minerals of different chemical composition and molecular structure combined together and form a new substance of different properties which we know as a rock. This is how rocks are formed and have it's own structure and chemical properties which we have studied in earlier blogs.
Minerals
Different types of rocks contains different types of minerals so based on this there are few minerals which form Igneous and Sedimentary rocks. All minerals contain wide range of characteristics so that they can form a rock in bulk or in lesser amount.
Types of minerals forming Igneous rocks:
1. Augite
It resemble hornblende. The crystals are prismatic and monoclinic. This mineral available in different colors like black, brown, greenish and violet brown. structure is uneven and brittle. It forms octagonal crystal. Changes to chlorite by hydration. Hardness as per Moh's hardness scale is 5.5-6.
Specific Gravity : 3.19 - 3.56
2. Chlortie
Chlorite is the largest group mineral which forms 90 percent of earth's crust of it. They are group of Phyllosilicate minerals. Main constituent present is silicate. This mineral available in different colors like green, red and rare yellow. They are obtained from augite, biotite and hornblende. Hardness as per Moh's hardness scale is 2-2.50.
Specific Gravity : 2.60 - 3.30
3. Feldspar
This is made up of tectosilicate minerals. It has many varieties like orthoclase, microline and little of plagioclase. Orthoclase is a straight splitting mineral available in grayish, whitish and pinkish color. Structure is tubular, well defined faces and cloudy appearance and rocks fractured easily if orthoclase present in large amount. Microline is also found with orthoclase in deep-green and flash-red color. Hardness as per Moh's hardness scale is 6-6.50.
Specific Gravity : 2.55 - 2.76
4. Hornblende
This is inosilicate series mineral. It is strong, heavy and durable mineral. It has glassy luster and uneven fracture pattern. It's structure looks like a hexagonal granular elongated type. It changes to chlorite mineral while come in to the weather contact. It is of dark green or black color. Hardness as per Moh's hardness scale is 5-6.
Specific Gravity : 2.90 - 3.40
5. Mica
This types of minerals are available in the form of distinct layer or say plates. They passes shiny surface too. In igneous rocks two common forms of mica present are muscovite and biotite. This forms are available individually or combined. Mica available in colors or colorless depending upon it's layered structure. Hardness as per Moh's hardness scale is 2-3. Mica also looses it's elasticity when open to atmosphere.
Specific Gravity : 2.8 - 3.0
6. Olivine
This mineral is used to make serpentine. It is of silicate group mineral. It is available in black, yellow and green color. It can fracture easily into pieces. Hardness as per Moh's hardness scale is 6.5-7.
Specific Gravity : 3.2 - 4.5
7. Plagioclase
Series of feldspar mineral having sodium, aluminium and silicate are fall into plagioclase category. Hardness as per Moh's hardness scale is 6-6.5.
Specific Gravity : 2.60-2.70
8. Quartz
This is a mineral form of silicon and oxygen constituent. Generally it has no distinct color. Due to oxides of metallic it is available in pink, yellow and brownish color. It is acid attack resistant and water resistant too. Most of the sands are available from quartz. Hardness as per Moh's hardness scale is 7.
Specific Gravity : 2.65
9. Serpentine
This is a group of kaolinite group minerals. It has a massive appearance. It has green and yellow color.
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