MINERAL AND ROCK ID QUIZ

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Magnetite

Mineral - Fe3O4

Strongly magnetic

High specific gravity

Lustre: Metallic dull

Colour: Black

Streak: Black

Hardness: 5.5-6

Rough fracture, no cleavage

Habit: octahedral crystals or massive

Galena

Mineral - PbS

Perfect 3 way cleavage at 90 degrees

High specific gravity

Habit: Cubic shape

Lustre: Metallic bright

Colour: Greyish blue

Streak: Greyish black

Hardness: 2.5-5.5

Hematite

Mineral - Fe2O3

Lustre: Metallic/ Earthy/ Dull

Colour: Reddish grey/ Black/Blackish red

Streak: Reddish brown

Hardness: 5.5-6.5

Rough fracture, no cleavage 

Habit: Massive, globular, octahedral crystals 

Pyrite

Mineral - FeS2

Habit: Cubic, isometric (More geometric than Chalcopyrite)

Lustre: Metallic

Colour: Pale brass yellow

Streak: Greenish black

Hardness: 5.5-6.5

Rough fracture, no cleavage

Chalcopyrite

Mineral - CuFeS2

Lustre: Metallic

Colour: Bright brass yellow (sometimes golden)

Streak: Greenish black

Hardness: 3.5 (2.5-5.5)

Weakly magnetic

Rough fracture, no cleavage

Habit: massive, possibly octahedral crystals

Calcite

Mineral - CaCO3

Strong reaction with acid

Perfect 3 way cleavage at 120/60 degrees

Lustre: Vitreous/ Glassy

Colour: Colourless/ White/ Yellow (could also be pink and brown sometimes)

Streak: White

Hardness: 3 (2.5-5.5)

Low specific gravity

Habit: prismatic

Pyroxene

Mineral

Perfect 2 way cleavage at 90 degrees

Lustre: Vitreous

Colour: Brown green, Green, Light brown, Dark brown, Black

Streak: Greenish white

Hardness: 5.5-6.5

habit: prismatic

Low specific gravity

Plagioclase

Mineral

Perfect 2 way cleavage at 90 degrees

Polysynthetic twinning/ Albite twinning

Lustre: Vitreous/ Glassy

Colour: White

Streak: White

Hardness: 6-6.5

Low specific gravity

Habit: prismatic

Quartz

Mineral - SiO2

Habit: Prismatic, massive

Conchoidal fracture

Lustre: Vitreous/ Glassy

Colour: Variable

Streak: White

Hardness: 7

Potassium Feldspar (Orthoclase)

Mineral

Perfect 2 way cleavage at 90 degrees

Perthitic texture

Carlsbad twinning

Lustre: Vitreous/ Glassy

Colour: Variable but Pink/Colourless/ White most common

Streak: White

Hardness: 6-6.5

Low specific gravity

Garnet

Mineral- index

Habit: Dodecahedron, isometric

Lustre: Vitreous/ Resinous

Colour: Reddish brown

Streak: White

Hardness: 7-8

Rough fracture, no cleavage 

Low specific gravity 

Amphibole

Mineral

60/120 degree cleavage, perfect in 2 directions

Lustre: Vitreous

Colour: Black

Streak: White

Hardness: 5.5-6.5

Low specific gravity

Habit: prismatic

Olivine

Mineral

Lustre: Vitreous/ Glassy

Colour: Yellowish green, Olive green, Greenish black (sometimes reddish brown)

Streak: White

Hardness: 6.5-7

Low specific gravity 

Conchoidal fracture, no cleavage

Habit: Equant prisms, massive

Muscovite

Mineral

Perfect one way (basal cleavage)

Lustre: Vitreous/ Pearly

Colour: White, Gray, Silver white

Streak: White

Hardness: 2.5

habit: platey

Low specific gravity 

Biotite (Black Mica)

Mineral

Perfect one way cleavage

Lustre: Vitreous/ Pearly

Colour: Black, Dark brown, Blackish brown

Streak: Grey

Hardness: 2.5

Low specific gravity

Habit: platey

Gypsum

Mineral

Lustre: Pearly, vitreous

Colour: White, Colorless, Yellowish white

Streak: White

Hardness: 2

Low specific gravity

Cleavage in 3 directions, 1 perfect, 2 less distinct

Habit: prismatic

Staurolite

Mineral- index, high grade

Penetration twins (Cross twins)

Lustre: Vitreous/ Dull

Colour: Brownish yellow, Brownish black, Yellow brown, Dark brown, Reddish brown.

Streak: Grey

Hardness: 7-7.5

Kyanite

Mineral- index, high grade

Habit: Blade-like

Lustre: Vitreous/ Pearly

Colour: Commonly blue (sometimes white, grey, green, black)

Streak: Grey

Hardness: Parallel = 4.4.5, Perpendicular = 6.5

Gabbro

Igneous rock

Composition: Mafic

Formation: Intrusive

Texture: Crystalline, Phaneritic

Minerals: Calcium rich: pyroxene; olivine; plagioclase feldspar; amphibole

Granite

Igneous rock

Composition: Felsic

Formation: Intrusive

Texture: Crystalline, Phaneritic

Minerals: Sodium rich: quartz; potassium feldspar; biotite; amphibole

Obsidian

Igneous rock

Composition: Felsic (glass is made of silica!)

Formation: Extrusive

Texture: Non-crystalline, Glassy

Conchoidal fracture

Pumice

Igneous rock

Composition: Felsic

Formation: Extrusive

Texture: Non-crystalline, Glassy

Light weight

Very porous

Basalt

Igneous rock

Composition: Mafic

Formation: Extrusive

Texture: Crystalline, Aphanitic

Minerals: Calcium rich: pyroxene; olivine; plagioclase feldspar; amphibole

Ash Tuff

Igneous rock

Composition: Felsic

Formation: Extrusive

Texture: Noncrystalline, Fragmental/pyroclastic

Andesite

Igneous rock

Composition: Mafic

Formation: Extrusive

Texture: Crystalline, Porphyritic

Minerals: Pyroxene; plagioclase feldspar; amphibole

2 stage cooling

Slate

metamorphic rock

Foliated

Sheet-like texture

Low grade

Fine-grained

Composition: Micas, quartz

Protolith: Mudstone/shale

Formation: Regional/dynamic

Schist

metamorphic rock

foliated

Medium grade

Medium coarse-grained

Composition: Micas, kyanite, garnet

Protolith: Mudstone/shale

Formation: Regional/dynamic

Gneiss

metamorphic rock

foliated

High grade

Medium coarse-grained

Composition: Quartz, feldspar

Protolith: Granite and mudstone/shale

Formation: Regional/dynamic

Marble

metamorphic rock

non-foliated

Low-high grade

Reacts strongly to acid

Hardness: 3

Composition: Calcite, dolomite

Protolith: Limestone

Formation: Contact

quartzite

metamorphic rock

non-folitated

Medium-high grade

No reaction to acid

Hardness: 7

Composition: Quartz

Protolith: Sandstone

Formation: Contact

Shale

sedimentary rock

clastic

Very fine grain

Well-sorted

Rounded grains

Environment: River, lake, swamp; less likely in tidal flat or lagoon

Lithic Sandstone (Greywacke)

sedimentary rock

clastic

>15% fine grained matrix like clay

Composed of mostly rock fragments

Fine-grained

Well sorted/ Poor graded

Angular, low sphericity

Environment: River (High energy settings)

Arkosic Sandstone (feldspar rich)

sedimentary rock

clastic

Coarse-grained

Poorly-sorted

Poorly rounded, low sphericity

Commonly reddish in colour

Environment: River (High energy settings)

Red sandstone (rich iron oxides)

sedimentary rock

clastic

Coarse-grained

Well-sorted

Rounded, high sphericity

Environment: Desert (red), beach, river

Conglomerate

sedimentary rock

clastic

Coarse-grained

Poorly sorted

Rounded, high sphericity

Grains of varying composition

Environment: River (Medium to high energy setting)

Chert

sedimentary rock

non clastic

Conchoidal fracture

Very fine-grained, undistinguishable grains

Contains mainly quartz

Environment: Deep marine

Limestone

sedimentary rock

non clastic

Reacts strongly with acid

Composed of Calcite

Medium to coarse-grained

May contain fossils

Environment: Shallow marine

Evaporite

sedimentary rock

non clastic

Composed of Halite/table salt or Gypsum

Medium to coarse-grained

Environment: Tide pools, lagoon