ENGINEERING GEOLOGY - MINERALS Engr. Imran Mehmood Civil Engineering Department Swedish College of Engineering & Technology, Wah Cantt Date # 28th December, 2011 – Lecture # 05 ENGINEERING GEOLOGY - MINERALS

MINERALS Visual Observation Pick up any rock and look at it carefully. You will probably see small, differently colored specks like those in granite. Each speck is a mineral. A Rock is an aggregate of Minerals

MINERALS - DEFINITION Definition A mineral is a naturally occurring, with a chemical composition and a crystalline structure. Currently more than 4,000 minerals are known. Some are strong & resistant to deterioration. However, some are soft and produce weaker rocks. Mineralogy Study of minerals, their properties and uses is known as mineralogy.

MINERALS – PHYSICAL PROPERTIES Following are the properties of minerals for their identification and to distinguish them from one an other. Structure Color Luster Streak Hardness Specific Gravity Cleavage Fracture

MINERALS – PHYSICAL PROPERTIES Structure The property, which indicates the order in which the atoms of a mineral are arranged. FIBROUS – when a mineral have thread like structure COLUMNAR – thick or thin column like structure GRANULAR – fine or coarse grains packed together

MINERALS – PHYSICAL PROPERTIES Color It is considered to be an important property to identify minerals. An experienced and skilled observer ca identify a mineral by observing its color.

MINERALS – PHYSICAL PROPERTIES Streak It is the color of fine powder of mineral, which is obtained by scratching or rubbing the mineral on a piece of an angular porcelain plate called “Streak Plate” Streak of a mineral is constant in color.

MINERALS – PHYSICAL PROPERTIES Hardness Resistance offered to abrasion. It is determined by the ease of difficulty in scratching it with an another mineral of same hardness. Talc and Gypsum can be scratched with the nail but Quartz can’t be with knife.

MINERALS – PHYSICAL PROPERTIES SPECIFIC GRAVITY Defined as the ratio of weight of mineral to an equal volume of water at 4˚C. SG depends on the weight and spacing between atoms of minerals. Mineral consisting of lighter and widely spaced atoms will have a low specific gravity. SG of all minerals is between 1-20 (most of the lie between 2-7)

MINERALS – PHYSICAL PROPERTIES CLEAVAGE Tendency of mineral to split up easily along certain parallel planes producing more or less a smooth surface. PERFECT, GOOD OR DISTINCT split up with ease give smooth planes POOR, IMPERFECT OR NONE don’t split with ease don’t give smooth planes

MINERALS – DESCRIPTION ANDALUSITE Composition Aluminum Silicate (Al2SiO3) Structre Fibrous Color Grey or Red Streak White SG 3.1-3.3 Cleavage Poor Fracture Even

Sr. # Name Str Color Luster Streak S.G. Hard. Cleav. Fract. 1. TALC Massive White/ Green Pearly White 2.8 1 Poor Uneven 2. GYPSUM Granular Yellow 2.3 2 Perfect Even 3. CALCITE Vitreous 2.71 3 4. FLOURITE Crystaline 3.13 4 5. APATITE 3.19 5 Conchoid 6. ORTHOCLASE 2.56 6 7. QUARTZ Crystalline Brown/ 2.62 7 8. TOPAZ 3.55 8 9. CORUNDUM None 4.1 9 10. DIAMOND Variable - 3.5 10

THANK YOU Engr. Imran Mehmood Civil Engineering Department Swedish College of Engineering & Technology, Wah Cantt Date # 28th December, 2011 – Lecture # 05