Geology

recognition exam

gold

metal

sulfur

non-metal

graphite

non-metal

Pyrite

sulfide
crystal: diamond - коцкички

Marcasite

sulfide
crystal: rhombic - локумчиња

Galena

sulfide
crystal: diamond - коцкички

Pyrrhotite

sulfide

Chalcopyrite

sulfide

fluorite

halide

halite

halide

magnetite

oxide
crystal: diamond
color: gray, black with brownish tint in reflected sun
Luster: Metallic
Streak: Black
Cleavage: Indistinct, parting on, very good
magnetic
strongly attracted to magnets

hematite

oxide

silica

oxide

chalcedony

oxide

opal

oxide

cassiterite

oxide

lepidocrockite

goethite (limonite)

manganomelane

calcite

carbonate
vitreous luster - resembles the luster of glass
usually white, but also colorless, gray, red, green, blue, yellow, brown, orange
white streak
basic
soft
forms bubbles with acid
perfect cleavage - cleave without leaving any rough surfaces; a full, smooth plane is formed where the crystal broke

clay shale

color: black, grey, but brown, off-white, red, green, and blue are common
soft - can be split easily into fragile slabs
acid test doesn't help, some shales will react with acid and others won’t
Fine-grained – Grains are too small to see with the naked eye

claystone

may be any color, but is generally greenish gray to grayish black
relatively soft

conglomerate

has little pebbles in it

feldspar

have cleavage
hard: can't make scratch
acid: nothing happens

gabbro

dark colored
it's hard, it can scratch glass
gabbro is made out of bigger pieces then basalt, which has smaller ones
can be confused with basalt, the difference is that gabbro has crystals in it
gabbro is a coarse grained rock, basalt is a fine grained rock

glauconite

light green streak
Color: Blue green, green, yellow green
can be confused with chlorite

granite

grainy structure
hard
identifying - look for rocks with crystals. Look for shiny, flat surfaces within the rock—these are the crystal faces

graywacke

greenish-gray color

gypsum

linear orthogneis

loess

lydite

lydite

limestone

makes bubbles with acid
limestone shouldn't be gray
granular texture
color: It can be yellow, white, or gray
limestone is usually gray, but it may also be white, yellow or brown. It is a soft rock and is easily scratched

marleystone

lymestone

mica shist

paleorhyolite

paragneis

quartzitic sandstone

quartz

no cleavage
Color: Colorless through various colors to black
Luster: Vitreous – waxy to dull when massive
Streak: White

sandstone

sandstone

stromactitic magmatite

syenite

texture: granular, and these rocks differ from granite only by the absence or scarcity of quartz
color: pale colored, grey and pink
fractional crystallization

trachyte

travertine

haematite

color: red
crystal: rhombic

fluorite

halide

limonite

Luster: Earthy
Color: Various shades of brown and yellow
Streak: Yellowish brown
Cleavage: Absent

aragonite

Color: White, red, yellow, orange, green, purple, grey, blue and brown
Cleavage: Distinct, imperfect, good
Luster: Vitreous, resinous on fracture surfaces
Streak: White - unrecognizable

magnesite

color: Colorless, white, pale yellow, pale brown, faintly pink, lilac-rose, grayish, yellowish, brownish, rarely colorless
cleavage: perfect
luster: Vitreous but also dull, earthy, chalky, rarely vitreous
streak: white
can be hard to identify and is often confused with howlite
makes bubbles with acid

siderite

dolomite

anhydrite

apatite

olivine

garnet

tourmaline

muscovite

color: white, transparent

biotite

color: black

chlorite

color: green like

kaolinite

phyllosilicate

montmorillonite

phyllosilicate

illite

serpentine

Analcime

tectosilicates
Color: White, colorless, gray, pink, greenish, yellowish
Cleavage: Very poor
luster: vitreous

Leucite

tectosilicates
Color: White to grey
White streak
vitreous luster
cleavage: very poor