EOSC 210 Rock and Mineral Quiz

Magnetite (iron ore)

Colour: black Lustre: metallic - dull Streak: grey/black Hardness: >5.5 Specific Gravity: high Cleavage: none MAGNETIC!

Amphibole (Hornblende variety)

Colour: black Lustre: non-metallic - vitreous Streak: grey Hardness: >5.5 Specific Gravity: average Cleavage: two at 120 and 60 degrees

Biotite Mica (black mica)

Colour: black Lustre: non-metallic - glassy Streak: grey Hardness: <2.5 Specific Gravity: low Cleavage: single, perfect - produces sheets

Pyroxene (Augite variety)

Colour: black/brown/green Lustre: non-metallic - vitreous Streak: white/brown Hardness: >5.5 Specific Gravity: average Cleavage: two directions at 90 degrees

Pyrite (fool's gold)

Colour: black/gold Lustre: metallic - bright Streak: black Hardness: >5.5 Specific Gravity: high Cleavage: none Fracture: conchoidal

Quartz

Colour: clear/white, can be different colours Lustre: non-metallic - glassy Streak: none Hardness: >5.5 Specific Gravity: low Cleavage: none (only crystal faces) Fracture: can be conchoidal

Garnet (crystal)

Colour: deep red Lustre: non-metallic -resinous Streak: none Hardness: >5.5 Specific Gravity: average Cleavage: none

Olivine

Colour: green/grey Lustre: non-metallic - vitreous Streak: white/green Hardness: >5.5 Specific Gravity: average Cleavage: poor in 2 directions - 90 degrees

Chalcopyrite (copper ore)

Colour: green/grey/gold Lustre: metallic - dull Streak: none (dark green?) Hardness: 2.5 < x < 5.5 Specific Gravity: average Cleavage: poor

Galena (lead ore)

Colour: grey/silver Lustre: metallic - bright Streak: grey Hardness: 2.5 < x < 5.5 Specific Gravity: high Cleavage: perfect in 3 directions

Orthoclase (Potassium Feldspar)

Colour: light pink/orange Lustre: non-metallic - vitreous Streak: white Hardness: >5.5 Specific Gravity: average Cleavage: one perfect, one good, 90 degrees

Hematite (iron ore)

Colour: red/brown, white specks Lustre: metallic - dull Streak: reddish brown Hardness: >5.5 Specific Gravity: high Cleavage: none

Plagioclase (Na-rich Feldspar)

Colour: white/grey Lustre: non-metallic - vitreous Streak: white Hardness: >5.5 Specific Gravity: average Cleavage: one perfect, one good, 90 degrees

Calcite

Colour: white/translucent Lustre: non-metallic - glassy Streak: white Hardness: 2.5 < x < 5.5 Specific Gravity: low Cleavage: perfect in 3 directions (75/55 degrees) REACTS WITH HCl

Muscovite (white/clear mica)

Colour: white/transparent Lustre: non-metallic - glassy Streak: white Hardness: <2.5 Specific Gravity: low Cleavage: single, perfect - produces sheets

Schist

Grain size: medium-coarse Texture: Schistosity (alignment of micas) Protolith: mudstone -visible crystals, mica rich

Gneiss

Grain size: medium-coarse Texture: gneissosity (light + dark bands) Protolith: almost anything -distinctive banding, Augen

Slate

Grain size: very fine Texture: slatey Protolith: mudstone -breaks easily into sheets

Marble

Mineral composition: calcite Texture: fine to coarse crystals (massive) -doesn't scratch glass, reacts strongly to HCl

Quartzite

Mineral composition: quartz Texture: fine to coarse crystals (massive) Protolith: quartz-rich siltstone -scratches glass, no reaction to HCl

Chert

black + red stripes

Microcrystalline Limestone

black, tiny crystals, no visible layers, some small white spots

Shale (mudstone)

black, visible layers

Phaneritic

coarse grained crystals, cooled slowly deep within the Earth, (plutonic/intrusive rocks)

Glassy

extrusive rocks, cooled very quickly at Earth's surface

Felsic

feldspar + silica, less dense, lighter in colour (quartz, orthoclase, plagioclase, muscovite)

Granite

felsic, crystalline - phaneritic

Aphanitic

fine grained crystals, cooled rapidly with restricted crystal growth (volcanic/extrusive rocks)

Lithic Sandstone (greywacke)

grey, visible grains

Porphyritic Andesite

intermediate, crystalline, porphyritic

Pumice

intermediate, noncrystalline - aphanitic

Ash Tuff

intermediate, noncrystalline - fragmental

Evaporite

large crystals, red + white

Red Sandstone

light coloured, pinkish-red stripes

Conglomerate

little pebbles in reddish white cement

Basalt

mafic, crystalline - aphanitic

Gabbro

mafic, crystalline - phaneritic

Obsidian

mafic, noncrystalline - glassy

Mafic

magnesium + iron, more dense, darker in colour (biotite, amphibole, pyroxene, olivine)

Porphyritic

mix of fine grained and coarse grained crystals, part of material grew slowly, part grew quickly, (volcanic/extrusive rocks)

Minerals

naturally occurring, inorganic, crystalline solids with specific chemical structures

Fragmental

pyroclastic rocks, fragments of broken rock matter

Pyroxene vs. Amphibole?

pyroxene = dull cleavages at 90 degrees amphibole = reflective cleavages at 60 or 120 degrees

Arkosic Sandstone

visible grains, reddish colour

Gypsum

Colour: white/grey Lustre: non-metallic - vitreous/pearly Streak: white Hardness: <2.5 Specific Gravity: low Cleavage: good in one direction, fair in two others (60/120 degrees)

Crystal Habits

Cubic - pyrite and galena Prismatic: quartz Dodecahedron: garnet

Kyanite

-blue colouring -found in schist and gneiss

Staurolite

-dark red/brown -has twinning -found in schist and gneiss