1. 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

2. 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

3. 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.

4. 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

5. 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

6. 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.

7. 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.

8. 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.

9. 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)

10. 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

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

12. 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

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