ROCK MINERALS

Rock Minerals

Abstract

As we know that rocks consist of many types of minerals. Here we are going to discuss certain minerals like feldspar, quartz, muscovite, biotitic micas, olivine, augite, hornblend, calcite and garnet. We will discuss firstly compare some common properties of these minerals and then the methods used for differentiation of thin samples and hand samples of these minerals. Then in the last section we have to write brief description of appearance of selected rock samples showing the part of that mineral ore also a brief statistical analysis showing various descriptive statistics about the concentrations of these minerals in rocks( Hampel, 1968,63). Brief statistical data of minerals is shown at the end.

Rock Minerals

Introduction

The feldspars are a group of minerals that have similar characteristics due to a similar structure. All feldspars have low symmetry, being only monoclinic, 2/m, to triclinic, bar 1. They tend to twin easily and one crystal can even be multiply twinned on the same plane, producing parallel layers of twinned crystals. They are slightly hard at around 6, and have an average density at 2.55 to 2.76. They have a rather dull to rarely vitreous luster. Crystals tend to be blocky. Some feldspars may be triboluminescent. They have two directions of cleavage at nearly right angles. Feldspars also tend to crystallize in igneous enviroments, but are also present in many metamorphic rocks. feldspars orthoclase is a common raw material for the manufacture of some glasses, some ceramics, such as porcelain, and as a constituent of scouring powder.

Color: clear when in its pure form

Crystal habit: six sided prism ending in a six sided pyramid

Crystal system: Trigonal

Melting point: 1650 degrees C.

Boiling point: 2230 degrees C.

Solubility: H2O insoluble

Cleavage: None

Fracture: Conchoidal

Mohs scale of hardness: 7 or lower in varieties that are impure

Luster: vitreous

Streak: white

Specific gravity: 2.65, can vary in impure varieties

Granite consists mainly of quartz, with a granular structure and crystals, different in size and color. Granite has high stability to friction. Due to the excellent chemical, physical and mechanical properties, granite got a wide use in building for the external finishing. In addition, table-tops for a kitchen, stairs and fountains are made from granite.

Granite is a magmatic breed, containing 60-65% feldspar (orthoclase and plagioclase), 20-30% quartz and 5-10% biotite, muscovite, sometimes augite. The most widespread structure of granite is even-grained type. Texture is massive. The basic colour background of granite is conditioned by coloring of prevailing feldspar - pink, yellow, red, green, grey and other. High decorative and durability qualities of granite and considerable prevalence of granite deposits, determine his wide use in the different types of building and in monumental architecture.( Chayes, 1952, 65)

Calcite has following properties:

Color is extremely variable but generally white or colorless or with light shades of yellow, orange, blue, pink, red, brown, green, black and gray. Occasionally iridescent.

Luster is vitreous to resinous to dull in massive forms.

Transparency: Crystals are transparent to translucent.

Crystal System is trigonal; bar 32/m.

Hardness is 3 (only on the basal pinacoidal faces, calcite has a hardness of less than ...