We have a rock and mineral ID test coming up

We got ah 40 rocks and minerals on there

21 minerals and 19 rocks

So let's get down to business

Start off with our minerals

Quartz

Quartz has a hardness of 7 and is the hardest mineral in this set

The luster is glassy

Non-metallic

But be careful because quartz can be almost any colour

It has concoidal fracture

No cleavage but is sometimes in crystal form

It has sharp edges and is a common rock forming mineral

Calcite

Has a hardness of 3 and can be scratched with a knife

It's lustre is vitreous to earthy and non metallic

It has good cleavage and is rhombic

It can be many different colours

and effervesces with a dilute ten percent HCL

Plagioclase

Has a hardness of 6 and a non metallic lustre

It streaks white and has good cleavage at right angles

And twinning striations

It's usually light in colour white or grey

Orthoclase

A hardness of 6

It's lustre is non metallic vitreous

It streaks white it has good cleavage at 90 degrees

Colour is most often light to medium red but

can be white grey or green

Biotite and Muscovite

With a hardness of 2.5 to 3 it's very soft

It's lustre is non metallic

Perfect basal cleavage

Splits off easily into thin sheets that are

elastic or plastic

The colour is opaque to translucent

Biotite is always black

Muscovite is brown light green or beige

Hornblende

With a hardness of 5.5 it's as hard as a knife

It's lustre is vitreous non metallic

It has a bright black splintery appearance

It's cleavage not always easy to see

Angles fifty six degrees and one hundred twenty four degrees

The colour is black to dark green or brown

Pyroxene

Hardness of 5.5 same hardness as a knife blade

The lustre is vitreous to glassy and non metallic

The colour is light to medium grey or green

has visible cleavage plains at approximately ninety degrees

Talc

With a hardness of 1 it's very soft

and can be scratched with a fingernail

The cleavage is perfect basal

The streak is white the lustre is pearly to greasy

non metallic silky appearance slippery to the touch

Colour is pale green white yellow or translucent

Pyrite

Hardness of 6 to 6.5 it's harder than a knife blade

The lustre is metallic it has no cleavage

And is massive

The streak is greenish or brownish black

The colour is opaque pale brass yellow

Sometimes called fools gold

And is harder than chalcopyrite

Chalcopyrite

It's hardness is 3.5 to 4 softer than a knife blade

It has no cleavage and is massive

The lustre is metallic

The streak is greenish black

Softer than pyrite

The colour is brassy to greenish yellow

Graphite

The hardness of 1 to 2

It's lustre is metallic to dull

The cleavage is perfect basal

The streak is black and it marks paper

Has a greasy appearance and feel

The colour is black to steel grey

Hematite

A hardness of 5.5 to 6.5

The lustre is mostly non metallic

Found in compact red earthy masses but can

also be metallic dull silver

The streak is always red

Red powder will come off in your hands

The colours are red reddish brown black or metallic steel grey

Magnetite

With a hardness of 6 it can't be scratched with a knife

It's lustre is sub metallic dull metal appearance

There is no cleavage and it is massive

The streak is black

It is magnetic and will affect a compass

The colour is iron black

Gypsum

With a hardness of 2 it scratches easily with a fingernail

Lustre is non metallic

Clear crystalline form called celonite

Compact variety called alabaster most often in massive form

Colour usually white also grey reddish or brown

Serpentine

With a hardness of 2.5 to 4

Cleavage is not prominent concoidal fractures

lustre is non metallic greasy to waxy

Texture often has greasy or slippery feel

And the colour is most often green

Barite

A hardness or 2.5 to 3.5

The lustre is non metallic vitreous often transparent or translucent

The streak is white

The cleavage is perfect basal and prismatic or

Could be massive with fractures

Specific gravity 4.3 to 4.6

Occurs in tabular crystals in granular form

or in compact masses resembling marble

Colour it's colourless to white yellow brown red green or black

Chrysotile

Hardness of 2.5 to 4

The texture it has flexible fibres which are easily separated

The lustre is non metallic and silky

Colours can be green white yellow or brown

Galena

Hardness of 2.5

Lustre is metallic

The specific gravity of 7.6

The streak is medium grey and colours are

medium to dark grey

The cleavage is parallel to crystal cube faces

Pyrrhotite

With a hardness of 3.5 to 4.5

The streak is greyish black

It has no cleavage and a specific gravity of 4.6

It may be yellow to bronze in colour

and tarnishes to iridescent colours

and may be magnetic and the lustre is metallic

Sphalerite

With a hardness of 3.5 to 4

The lustre can be black variety metallic or

other common colours that are non metallic

It has cleavage with a specific gravity to 3.9 to 4

The streak is brown

Colours can be yellow brown red or black

if iron is present

All right that will do the minerals

now let's get into the rocks

We're gonna start off with granite

It's texture is panoritic medium to coarse grained

The structure is massive

The colour is white to grey mostly pink

The hardness is greater than 5.5

It's composition is made up of quartz

orthoclase plagioclase biotite and hornblende

Basalt

Texture is affinitic fine grained

Structure is massive vesicular amygdaloidal

flow pillows ropey blocky or columnar

The colour is dark grey to black

The hardness is greater than 5 to 6

It's composition consists of

plagioclase pyroxene olivine and some hornblende and biotite

Limestone

Texture is calcareous coarse grained

The structure is characteristically thick bedded to

massive may contain fossils

particularly in the cement

The colour is variable

The hardness is between 3 and 4

Composition it must consist of fifty percent

or more of calcite

Shale

Texture is fine grained

Structure is laminated splits into thin plates

may contain fossils

Colours are light to dark grey

iron oxides may give brown and red colours which are dull

The hardness is soft easily scratched and weathered

may disintegrate in humid climates

It's composition consists of

silt and clay size particles and clay minerals

Gneiss

Texture is uneven granular

medium to coarse grained crystalline

Structure

Gneissic banding parallel mineral orientation

alternating light and dark bands

Colour is light granular layers and

dark foliated bands

The hardness

Granular layers 6 to 7

foliated layers 2.5 to 3

It's composition consists of

orthioclase quartz biotite hornblende

and it is named for parent rock

Marble

Texture is even granular

fine to medium grained calcite crystals

Structure is massive

Colour is white but accessory minerals will colour the rock

The hardness is 3 is easily scratched

and easily eroded

It consists of calcite or dolomite

Rhyolite

Texture is aphanitic may be porphyritic

medium to coarse grained

Structure is massive

Colour is light grey yellow and red

The hardness is 6 to 6.5

The composition consists of

Quartz sanidine feldspar biotite and hornblende

Andesite

Texture is aphanitic may be

porphyritic fine grained

The structure is massive

Colour is brown green and dark grey

Hardness is 5 to 6

and it's composition consists of

plagioclase hornblende pyroxene and biotite

Diorite

Texture is phaneritic

coarse grained structure is massive

Colour is light to dark grey

Hardness is 5.5 to 6

The composition consists of

greater than ten percent of quartz

with orthioclase plagioclase hornblende and biotite

Gabbro

Texture is phaneritic coarse grained

The structure is massive

The colour is dark grey or greenish black

The hardness is greater than 5.5

and the composition consists of

plagioclase pyroxene hornblende and olivine

Porphyry

The texture is porphyritic

it has coarse crystals it's a light colour matrix

The background is fine grained and dark colour

ahh the colour varies

The hardness is greater than 5.5

usually picked from the individual mineral

the composition varies

Nepheline Syenite

Texture is phaneritic and coarse grained

Structure it has poor cleavage

is translucent with greasy to glassy lustre

The colours can be white yellow grey green

or even reddish or pink

The hardness is around 5.5 to 6

The composition consists of

sodalite apatite pyroxene sphene and feldspar

Limestone

Texture calcareous rock fine grained

Composed mainly of the mineral calcite

The structure stratification usually indistinct

sometimes fossils present on surface of rock

colour is variable

The hardness is ahh 3 to 4

dense variety's break with a concoidal fracture

It must consist of fifty percent or more

of calcite

Dolomite

Texture is coarse to fine grained

Structure is massive

Colour is white colourless buff brown pink or grey

Hardness is 3 to 4

effervesces very slowly in cold hydrochloric acid

Sandstone

Texture

even granular sand size

Structure is massive bedded cross bedding

and ripple marks

Colour varies depending on cement

white tan brown red or green

Hardness varies depending on cementing materials

quartz grains

The composition consists of quartz grains

if feldspar grains called arcos silica carbonates clay

or iron oxides as cementing agents

Talc Schist

Texture is medium to coarse grained

talc feel and flakeyness

Structure

Schistose foliation parallel alignment of

flaky minerals make more than fifty percent

Colour is silvery white grey yellow to brown

tones from iron oxides

Hardness and ease of splitting depends on