Earth Science (Minerals 1)

Igneous Rock (intrusive)

Formed from the cooling and solification for magma or lava and minerals begins to crystallize.

Sedimentary rock

formed from deposits of pre-existing rocks that accumulate on Earth's surface. If sediment is buried deeply, it becomes compacted and cemented forming a rock

Metamorphic rock

Formed when existing rocks are changed by heat, pressure

Mineral

Naturally occurring, inorganic solid made of elements
arranged to form a crystalline structure. They have defined
chemical formula and characteristic physical properties that all
geologists can test and observe to identify them

Naturally occuring

inorganic solid

crystalline

narrowly-defined chemical coposition

characteristic physical property

Magma

Molten rock/liquid in the earth’s crust

Lava

liquid/molten rock above the earth’s crust

Mineral Lustre

The way a mineral interacts with light

Metallic Lustre

Reflects all light, can be shiny or dull like a metal. Has a strongly colored streak

Non metallic mineral lustures

Transmits or absorbs some light, let’s it pass through surface. Has white, light or no colored streak

Mineral hardness

It is determined by rubbing a mineral of unknown hardness against one of
known hardness or vice versa.

Mohs scale (relative hardness 1 to 10), absolute hardness values (0 - 100)

Mineral fracture

The way a mineral breaks in a more or less random pattern with no smooth planar surfaces.

Uneven/Irregular fracture

A rough surface with irregular breaks, with no reflection of light

Conchoidal fracture

Smooth, curved, rippled planar surface, like a seashell, which reflects light.

Cleavage fracture

Flat smooth planes

Reflects light uniformly

Planes

The flat parallel sides of a mineral

Mineral streak

The color of the powder produced when a mineral is rubbed or scraped across a hard, unglazed surface like a streak plate

(Greater than 6.5 on the hardness scale)

Crystal habits of a mineral

the characteristic external shape or form of a mineral which is determined by its atomic structure

Mineral density

refers to the mass of minerals contained within a specific volume of a mineral or a substance.

Mineral hardness less than 2.5

If your finger nail can leave a scratch on the mineral

Greater than mohs scale hardness of 5.5

Leaves a scratch mark on glass surface

Diagnostic property

a single property that helps you quickly identify a mineral

Exsolution Lamalle

• Color variation in orthoclase,

• Occurs only in minerals whose compositions vary between two or more pure end member compositions – like K or Na

Schiller Effect

Iridescent

Silicate

SiO

• most abundant element which makes up the earth’s crust

(Example: Quartz, SiO2)

Lustre of Silicate

This mineral always has a non-metallic lustre

Streak of Silicate

The streak of this mineral is always white, pale grey, none at all

Non-ferromagnesian Silicate

SiO

• does not contain iron and magnesium

Color of non-ferromagnesian silicate

The color of this mineral is light

Ferromagnesian Silicate

SiO which contains Fe and/or Mg

(example: Olivine, (Fe,Mg)²SiO4

The color of Ferromagnesian Silicate

The color of this mineral is usually dark green, brown or black

Sulphides

S (Pyrite FeS²)

Lustre of Sulphide

This mineral will always have a metallic lustre

Streak of Sulphide

The streak of this mineral is always grey

Oxide

O (Example: Magnetite Fe³O4).

Lustre of Oxide

This mineral is considered metallic even if it has an earthy lustre

Streak of Oxide

This mineral’s streak is reddish brown or dark grey/black

Sulphates

SO4 (Example: Gypsum CaSO4.2H²O)

Halides

Contains F (Flouride), CI (Chloride), Br (Bromide), I (Iodide), At (Astatine)

Example: Halite, NaCI

Diagnostic property of Halides

Softness, between 2.5 and 5.5 on the mohs scale

Streak of Halides & Carbonates

The streak color of this mineral is generally white

Native elements

One single element, (Example: Graphite, C)

Carbonates

CO³ (Example: Calcite CaCO³)

Diagnostic property of Carbonates

This mineral will react with acid

Phosphate

PO4 (Example: Apatite, CA5(PO4)³F

Albite Twinning

A set of parallel lines on a certain crystal, seen on cleavage faces like albite and labradorite