Download presentation
Presentation is loading. Please wait.
1
PHYSICAL PROPERTIES OF MINERALS
Determine by simple test. Useful on field for recognizing. Identification by polarizing microscope by cutting minerals into thin slices and passing polarized light to pass through them.
2
PHYSICAL PROPERTIES OF MINERAL ARE:-
COLOURS )TENACITY STREAK )MAGNETISM LUSTRE )FLUORESCENCE HARDNESS )SPECIFIC GRAVITY HABIT )FORM CLEAVAGE FRACTURE FEEL
3
COLOURS Absorption of the certain wave lengths of light by atoms making up the crystal. Colour and appearance in light depends upon the composition and structure of the substance. Phenomenon shown by minerals:-
4
PLAY OF COLOURS:- It is the development of series of prismatic colour shown by some on turning them in light. E.g.: Diamond
5
b) CHANGE OF COLOURS:-It is similar to play of colour except that the rate of change of colour on rotation is rather low. E.g.: Plagioclase Feldspar.
6
c)IRIDESCENCE: Some minerals shows rainbow colours either in their exterior or in the interior surface.E.g.:-Limonite.
7
STREAK The colour of mineral powder is called the streak.
Obtained by rubbing the mineral against an unglazed porcelain plate , called the “streak plate”, . Important in case of coloured minerals which often give a much lighter streak the their original body colour .
8
LUSTURE The way of mineral, which reflect the light from its surface and may define as shine of mineral. There are two types of lusture:- 1)Metallic lusture 2)Non-metallic lusture
9
METALLIC LUSTURE NON-METALLIC LUSTURE
10
HARDNESS Define as the resistance of a mineral to scratching or abrasion. Hardness is determined by rubbing a mineral of unknown hardness against one of known hardness. Obtained by using “mohs scale of hardness". It can also be obtained by 1)scratch with finger nails , 2)a penknife, 3)penny
12
FINGER NAILS PENNY BY KNIFE
13
HABIT “Habit” of a mineral may be define as the size and shape of the crystals, and the structure or form shown by the crystal. 1)Accicular :- Minerals showing needle like crystals. E.g.:-Natrolite.
14
2)Fibrous:-Minerals showing an aggregate of long thin fibers. E. g
2)Fibrous:-Minerals showing an aggregate of long thin fibers. E.g.:-Asbestos. 3)Tabular:-Minerals showing bladed habit occur as small knife blades.E.g.:-Kyanite.
15
4)Granular:-Minerals which occur as aggregate of equidimensional grains.E.g.:-Chromites. 5)Pisolitic:-Minerals which occur as aggregates of rounded grains of a pea size. E.g.:-Bauxite.
16
6)Botryoidal:-Minerals showing aggregate of rounded masses resembling bunch of grapes. E.g.:-Chalcedony. 7)Columnar:-Minerals showing columnar crystals. E.g.:- Tourmaline.
17
CLEAVAGE The tendency of a mineral to break more easily with smooth surfaces along planes of weak bonding. It is the property which is related to the atomic arrangement within the mineral. For E.G.:-Mica,Galena,Calcite.
18
Mica has basal cleavage.
Calcite has rhombohedral cleavage. Galena has cubic cleavage.
19
FRACTURE The way a mineral breaks when it does not yield along cleavage or parting surface , it is called Fracture. Fracture are neither linear nor parallel. CONCHOIDAL FRACTURE
20
EVEN FRACTURE:- Fracture surface which is almost flat.
UNEVEN FRACTURE:- Fracture surface which is irregular or rough. E.g.:DUMORTIERITE
21
Minerals can be identified by how they break
Minerals can be identified by how they break. Obsidian (left), although not a mineral because of its lack of crystal structure, shows excellent conchoidal fracture. Asbestos (right), which is the common name for several minerals that form thin, threadlike structures, is an example of a mineral with fibrous fracture.
22
FEEL Feel is the sensation upon touching or handling minerals .the different types of feel are “greasy” , “soapy”, “rough” , and “harsh” . Talc has “greasy” feel.
23
Kaolin has “Soapy” feel.
Bauxite has “Rough” feel.
24
TENACITY Tenacity of mineral denotes the degree or character of cohesion. Tenacity is classified as follows:- 1)Sectile:-Mineral which may be cut with knife but slices are not malleable. ORPIMENT
25
2)Malleable:-Minerals which flatten under the hammer.
GOLD 3)Flexible:-Minerals which may be bent. GYPSUM
26
MAGNETISM A few minerals are attracted by magnet . Of these minerals magnetite and pyrrhotite are the most common examples. The magnetite that possesses attracting power and polarity is called “Lodestone”. MAGNETITE
27
FLUORESCENCE Some minerals when exposed in sunlight or ultraviolet light, produce a colour quit different from their own. Thus green or colourless fluorite shows a blue or purple colour in ultraviolet light. This property of minerals is called “Fluorescence”.
28
IN SUNLIGHT SHOWS BLUE OR PURPLE COLOUR GREEN FLUORITE
29
SPECIFIC GRAVITY “Specific gravity” is a number which represents the ratio of the weight of a mineral to the weight of an equal volume of water. Thus a mineral with specific gravity 4.0 is four times as heavy as water.
30
FORM The internal atomic arrangement of a mineral is manifested outwardly by development of geometrical shapes of crystal structure. CALCIT INTERNAL CRYSTAL STRUCTURE
31
COMPARISION OF MINERALS
PYRITE HEMATITE FORMULA FeS2 Fe3O3 IMAGE COLOUR BRASS YELLOW REDDISH BROWN OR BLACK LUSTURE METALLIC METALLIC TO DULL STREAK GREENISH OR BROWNISH BLACK DARK RED HARDNESS 6-6.5 5-6 HABIT COMMON FORMS ARE THE CUBE CRYSTALS THIN TABULAR USE MANUFACTURE OF SULFURIC ACID AS IRON ORE,AS PIGMENT CLEVAGE - ABSENT
32
MINERAL MAGNETITE BAUXITE FORMULA Fe3O4 Al2O3 IMAGE COLOUR IRON BLACK WHITE,GRAY,YELLOW, BROWN LUSTURE METALLIC TO DULL DULL EARTHY STREAK BLACK YELLOW TO BROWN HARDNESS 6 2-2.5 HABIT OCTAHEDRAL CRYSTAL,MASSIVE OR GRANULAR PISOLITIC USE IMPORTANT ORE OF IRON AS ABRASIVE MATERIAL,IMPORTANT ORE OF ALUMINIUM CLEVAGE ABSENT
33
MINERAL GYPSUM DOLOMITE FORMULA CaSO4.2H2O CaMg(CO3)2 IMAGE COLOUR COLOURLESS,WHITE,GREY,RED OR BROWN WHITE,GRAY TO PINK LUSTURE USUALLY VITREOUS VITREOUS TO PEARLY STREAK WHITE HARDNESS 2 3.5-4 HABIT TABULAR,FIBROUS,GRAN-NULAR. CRYSTAL SHOW CURVED FACES USE POP , AS FERTILIZER AS BUILDING & ORNAMENTAL STONE CLEAVAGE PERFECT PERFECT ON RHOMBOHEDRAL CLEAVAGE
34
MINERAL CALCITE GRAPHITE FORMULA CaCO3 C IMAGE COLOUR USUALLY WHITE TO COLOURLESS IRON BLACK TO STEEL GRAY LUSTURE VITREOUS METALLIC ,EARTHY STREAK WHITE BLACK HARDNESS 3 1-2 HABIT CRYSTALLINE,TABULAR,GRANULAR USE MANUFACTURE OF CEMENT AND LIME. STEEL MAKING,LUBRICANTS CLEVAGE PERFECT WITH ’ PERFECT
35
MINERAL CHALCOCITE GALENA FORMULA Cu2S PbS IMAGE COLOUR DARK GRAY TO BLACK LEAD GRAY AND SILVER LUSTURE METALLIC BRIGHT METALLIC STREAK SHINY BLACK TO LEAD GRAY LEAD GRAY HARDNESS 2.5-3 2.5 HABIT SHORT PRISMATIC CRSTAL,MASSIVE OFTEN CUBIC CRYSTAL,MASSIVE USE IMPROTANT ORE OF COPPER IMPORTANT ORE OF LEAD AND SILVER CLEAVAGE POOR PERFECT CUBIC
Similar presentations
