2. MINERALS. What is mean by Mineral.
A Substance That Have The Following Requirements, Then That
Substance Called A Mineral.
1. Natural Occurring.
2. Inorganic.
3. Solid.
4. Definite Crystal Structure.
5. Definite Chemical Composition.
What Is Mean By That.
➢ Natural Occurring.
❑ Not Made By Man Means Natural Occurring.
3. MINERALS.❑Means taken from the Nature.
❑E.g. Steal is not a mineral because it is not a natural occurring substance.
➢Inorganic.
❑Means not from the living things and there remains mean fossils and tree
biomass etc.
❑E.g. Crude oil, Coal, Gas are not minerals because these are taken from the
fossils of living organisms and from biomass.
➢Solid.
❑A mineral must be in solid.
❑Means that a mineral can’t b in a liquid and gas form.
❑If it is in liquid or gas form then it is not called a mineral.
4. MINERALS.➢Definite Crystal Structure.
❑The atoms that the mineral are made of are connected to each other in a
pattern.
➢Definite Crystal Structure.
❑This means that there is a specific chemical formula for each mineral.
❑The mineral pyrite is made of 1 atom of iron form every 2 atoms of
sulfur.(FeS2)
❑Pyrite will have the same chemical formula regardless of where it is found.
➢Definition Of Miner.
❑A Mineral must be natural occurring, inorganic, solid and have definite
crystal structure and chemical composition.
10. MINERALS.❖How To Identify A Mineral.
❖Minerals can be identified by their characteristics or by their physical
properties.
❖Physical Properties Of Minerals.
✓Color.
➢ Color is a physical property that is easily observed. It is helpful to identify
a mineral easily but not so because most minerals can be have a wide
range of colors due to small amounts of impurities in them.
➢ E.g. Quartz crystals are found with white, pink, black, yellow, purple and in
many others colors.
11.
12. MINERALS.✓ Streak.
➢ Streak is the color of the powdered mineral when rubbed on a hard
porcelain tile.
➢ Streak maybe completely different from the color of the hand specimen.
➢ Streak is more diagnostic then color.
13.
14. MINERALS.✓ Luster or Lustre.
➢ Is a Latin word lux means light.
➢ Light reflected from the surface of a mineral is Known a luster.
➢ Minerals are primarily divided into two types of luster.
1) Metallic Luster.
2) Non Metallic Luster: Non Metallic Luster is further divided in to following
types. Adamantine, Dull, Greasy, pearly, Resinous, Silky, vitreous and Waxy
Luster.
❖ Note.
➢ The Luster of a mineral which does not quite possess a metallic luster is
termed as Sub Metallic Luster.
15. MINERALS.o Metallic Luster.
➢ Minerals possessing metallic luster are opaque and have very high
reflectance.
➢ E.g. Metallic Luster in galena, Gold, Magnetite, chalcopyrite, Pyrite.
o Sub Metallic Luster.
➢ Sub Metallic Luster Minerals have similar luster to metal, but are duller
and less reflective. It is also opaque.
➢ Sub Metallic Luster In Hematite.
22. MINERALS.o Non Metallic Luster.
➢ Those Minerals that do not look like metallic.
➢ Non Metallic Luster Minerals are further divided into following categories.
o Adamantine Luster.
➢ Minerals that have remarkable shine and brilliance and have the hard look
of a diamond are called adamantine Luster. These minerals can be
transparent and translucent. The most popular example are found in
jewelry and accessory shop. Diamond And Cubic Zirconia.
23. MINERALS.o Dull Or Earthy Luster.
➢ Dull Luster is also known as earth luster, and is used to describe minerals
that have poor reflectivity. The surface of minerals with dull luster is
coarse and porous.
➢ E.g. Kaolinite, montmorillinite and etc.
24. MINERALS.o Vitreous Luster.
➢ The reflective property of minerals with vitreous luster is similar to that of
glass. This is a very common types of luster and can occurs in minerals
that are transparent and translucent.
➢ E.g. Quartz, Calcite and etc.
25. MINERALS.o Greasy Luster.
➢ The Greasy type of luster can be found in minerals that look like they were
coated with oil or grease. These minerals can also be said to resemble fat
and they also feel greasy to touch.
➢ Halite, opal and etc.
26. MINERALS.o Pearly Luster.
➢ Pearly minerals consist of thin transparent co-planner sheets. Light
reflecting from these layers give them lustre reminiscent of pearls. Such
Minerals posses perfect cleavage.
➢ E.g. Muscovite, Stilbite and etc
27. MINERALS.o Resinous Luster.
➢ Resinous Minerals have the appearance of resin, chewing gum or ( Smooth
surfaced) Plastic.
➢ A principle example is amber, which is a form of fossilized resin.
28. MINERALS.o Silky Luster.
➢ Silky minerals have a parallel arrangement of extremely fine fibers, giving
them a lustre reminiscent of silk.
➢ E.g. Asbestos, Ulextie and Satin spar variety of gypsum.
30. MINERALS.o Hardness.
➢ Hardness is measured by the resistance which a smooth surface offers to
abrasion. The degree of hardness is determined by observing the
comparative ease or difficulty which one mineral is scratched by another.
➢ To find the hardness of a mineral we still use mohs relative hardness
scale.
32. MINERALS.
Friedrich Mohs.
➢ In 1822 the Austrian mineralogist Friedrich Mohs devised a scale based on
one mineral's ability to scratch another. He placed 10 minerals in order
from softest to hardest, giving a relative hardness value of 1 to the softest
mineral, and 10 to the hardest. Each mineral in the scale scratches the one
below it (the lower number) but not the one above it (the higher number).
This became known as Mohs' scale of hardness, and is still one of the best
practical methods of estimating a mineral's hardness. Mohs designated ten
minerals for his scale from hardest (10) to softest (1) (listed with objects
of equivalent hardness):
34. MINERALS.o Cleavage And Fracture.
➢ Cleavage and Fracture both describe different ways in which a mineral
can break.
➢ Cleavage.
➢ The tendency of a mineral to break along flat planar surfaces as
determined by the structure of its crystal lattice. These two-dimensional
surfaces are known as cleavage planes and are caused by the alignment of
weaker bonds between atoms in the crystal lattice.
➢ Cleavage Terms. (Only use if cleavage plans can be recognized)
1. Perfect: Produces smooth surfaces ( Often seen as parallel sets of
straight lines, E.g. Mica.
2. Imperfect: Produces planes that are not smooth, E.g. pyroxene.
➢ In Detail The Table Is Given Below.
36. MINERALS.o Fracture.
➢ If a mineral is strained beyond its elastic limits, it will break. If it breaks
irregularly then it shows fracture.
➢ Fracture terms (use in all other cases):
1. Conchoidal - Fracture surface is a smooth curve, bowl-shaped (common in
glass);
2. Hackly - Fracture surface has sharp, jagged edges;
3. Uneven - Fracture surface is rough and irregular;
4. Fibrous - Fracture surface shows fibres or splinters.
37. MINERALS.o Density.
Density is an intrinsic physical property of minerals that relates to the
composition of the mineral and to the pattern in which the mineral’s atoms
are arranged. “Intrinsic” means that the property is the same for the
mineral, no matter what the size or shape of the sample.
o Specific Gravity.
➢ A mineral's specific gravity is the ratio of its mass to the mass of an equal
volume of water. For example, magnetite has a specific gravity value of 5.2,
meaning 1cm3 of magnetite will be 5.2 times as heavy as 1cm3 of water.
38. MINERALS.➢ Water has a specific gravity of 1.0. If a mineral has a specific gravity of 2.7,
it is 2.7 times heavier than water. Minerals with a specific gravity under 2
are considered light, between 2 and 4.5 average, and greater than 4.5
heavy. Most minerals with a metallic luster are heavy. The specific gravity
may slightly vary within a mineral because of impurities present in the
minerals structure.
39. MINERALS.o Transparency.
➢Transparency refers to the degree to which light can pass through a mineral.
➢Transparency Terms.
➢Opaque - no light can pass through the mineral.
➢Translucent - light can pass through the mineral but is diffused so that
images cannot be seen clearly.
➢Transparent - light can pass through the mineral and images can be seen
clearly.
40. MINERALS.o External Crystal Form.
➢ A set of faces that have a definite geometric relationship with one
another. Crystal faces are a reflection of an orderly internal atomic
arrangement Most minerals grow while competing for space with other
minerals Orderly set of faces that make up a crystal form can develop only
in specialized conditions. Most minerals can develop their characteristic
crystal faces only when they are surrounded by fluids that can be easily
displaced as crystal grows
➢ Few minerals such as garnet are able to overpower and displace
surrounding solid material during growth, hence always develop their
crystal faces
41. MINERALS.o Tenacity.
➢ Tenacity describes the reaction of a mineral to stress such as crushing,
bending, breaking, or tearing. Certain minerals react differently to each
type of stress. Since tenacity is composed of several reactions to various
stresses, it is possible for a mineral to have more than one type of
tenacity. The different forms of tenacity are:
➢ Brittle .
➢ If a mineral is hammered and the result is a powder or small crumbs, it is
considered brittle. Brittle minerals leave a fine powder if scratched, which
is the way to test a mineral to see if it is brittle. The majority of all
minerals are brittle.
➢ E.g. Quartz.
(Minerals that are not brittle may be referred to as Nonbrittle minerals.)
42. MINERALS.➢Sectile .
➢Sectile minerals can be separated with a knife, much like wax but usually not
as soft.
➢E.g. Gypsum.
➢Malleable.
➢If a mineral can be flattened by pounding with a hammer, it is malleable. All
true metals are malleable.
➢E.g. Silver.
➢Ductile .
➢ A mineral that can be stretched into a wire is ductile. All true metals are
ductile.
➢ E.g. Gold.
43. MINERALS.➢Flexible but inelastic - Any mineral that can be bent, but remains in the new
position after it is bent is flexible but inelastic. If the term flexible is
singularly used, it implies flexible but inelastic.
➢E.g. Copper.
➢Flexible and elastic - When flexible and elastic minerals are bent, they
spring back to their original position. All fibrous minerals, and
some acicular minerals belong in this category.
➢E.g. Chrysotile Serpentine.
44. MINERALS.✓ Minerals Uses.
➢ Minerals are the source of metals, gemstones, and other materials used to
make many products.
➢ Gemstones.
1. Gemstones are hard, colorful and have a brilliant or glassy luster.
2. Gemstones are valued for their color, luster and durability.
3. Once cut a gemstone is referred to as a gem.
➢ Metals.
1. Metals are useful because they can be stretched into wire or hammered
into sheets.
2. Metal is use in making tool framing buildings and even the filament in a
light bulb.
45. MINERALS.➢ Other Uses.
➢ Some minerals are used in foods, medicines, fertilizers and other building
materials.
