Rocks and Minerals
8. Cleavage
Minerals Ability of a mineral to break/split apart along various
planes.
– naturally-occurring chemical compound, using in
crystalline form and inorganic in origin and has a specific 9. Fracture
chemical composition
Describes how a mineral break when broken contrary to
Mineralogy – study of minerals its natural cleavage planes.
Examples: Conchoidal (Quartz), Splintery (Kyanite)
Properties of minerals 10. Specific Gravity
1. Luster Ration of the density of the mineral to the density of
water.
Ability of a mineral to reflect light from its surface.
Other special properties
Examples: Adamantine (diamond) Metallic (Magnetite) Taste, odor, attraction to magnets, fluorescence,
radioactivity, and reactivity.
2. Diaphaneity
Ability of a mineral to transmit light.
Examples: Transparent, Translucent, Opaque
Mineral Groups
3. Color
Not a reliable property in identifying minerals. a. Silicate Minerals
- the presence of impurities may alter the color of a - rock-forming minerals that contain the elements
mineral. oxygen, silicon, aluminum, iron, calcium, sodium,
potassium, and magnesium.
4. Streak
Silicon + Oxygen = Silicate
The color of the mineral in powder form.
Feldspar – most abundant mineral (50% of the earth’s
- a mineral’s streak can be obtained by rubbing it crust)
on a surface of a porcelain and observing the color of its
mark. Quartz – only silicate mineral purely made of O and Si and
is second most abundant mineral on the earth’s crust.
5. Crystal shape
Other example: mica, amphibole, pyroxene, olivine
Common or characteristics shape of crystal or
combination of crystals.
Examples: Octahedron (Magnetite crystals) Cube (Halite) b. non-silicate minerals
6. Tenacity less abundant in earth’s crust. Some common non-
Mineral’s toughness or resistance to breaking or silicates are oxides, carbonates, sulfates, and halides.
These are the main components of sediments and other
deforming. sedimentary rocks.
Examples: Brittle (Fluorite), Malleable (copper) Economic importance:
7. Hardness Calcite – main component of limestone; used in the
production of cement.
Resistance of the mineral to abrasion or scratching.
Copper – conductor of electricity
- Mohs Scale of Hardness consist of ten (10)
minerals arranged in order from 1 to 10, 1 being the Important ores of iron like hematite and magnetite.
softest and 10 being the hardest.
8. Cleavage
Minerals Ability of a mineral to break/split apart along various
planes.
– naturally-occurring chemical compound, using in
crystalline form and inorganic in origin and has a specific 9. Fracture
chemical composition
Describes how a mineral break when broken contrary to
Mineralogy – study of minerals its natural cleavage planes.
Examples: Conchoidal (Quartz), Splintery (Kyanite)
Properties of minerals 10. Specific Gravity
1. Luster Ration of the density of the mineral to the density of
water.
Ability of a mineral to reflect light from its surface.
Other special properties
Examples: Adamantine (diamond) Metallic (Magnetite) Taste, odor, attraction to magnets, fluorescence,
radioactivity, and reactivity.
2. Diaphaneity
Ability of a mineral to transmit light.
Examples: Transparent, Translucent, Opaque
Mineral Groups
3. Color
Not a reliable property in identifying minerals. a. Silicate Minerals
- the presence of impurities may alter the color of a - rock-forming minerals that contain the elements
mineral. oxygen, silicon, aluminum, iron, calcium, sodium,
potassium, and magnesium.
4. Streak
Silicon + Oxygen = Silicate
The color of the mineral in powder form.
Feldspar – most abundant mineral (50% of the earth’s
- a mineral’s streak can be obtained by rubbing it crust)
on a surface of a porcelain and observing the color of its
mark. Quartz – only silicate mineral purely made of O and Si and
is second most abundant mineral on the earth’s crust.
5. Crystal shape
Other example: mica, amphibole, pyroxene, olivine
Common or characteristics shape of crystal or
combination of crystals.
Examples: Octahedron (Magnetite crystals) Cube (Halite) b. non-silicate minerals
6. Tenacity less abundant in earth’s crust. Some common non-
Mineral’s toughness or resistance to breaking or silicates are oxides, carbonates, sulfates, and halides.
These are the main components of sediments and other
deforming. sedimentary rocks.
Examples: Brittle (Fluorite), Malleable (copper) Economic importance:
7. Hardness Calcite – main component of limestone; used in the
production of cement.
Resistance of the mineral to abrasion or scratching.
Copper – conductor of electricity
- Mohs Scale of Hardness consist of ten (10)
minerals arranged in order from 1 to 10, 1 being the Important ores of iron like hematite and magnetite.
softest and 10 being the hardest.
