Practical Test Minerals Flashcards
1
Q
Quartz
A
Milky white (or clear or pink or prpl) White streak No cleavage Conchoidal 7 Diag: fracture Found in granite
2
Q
Oligoclase (plagioclase feldspar)
A
Creamy beige White streak Vitreous 2 good cleavage @ 90° Irregular fracture 6-6.5 Diag: cleavages
3
Q
Microcline K/alkali feldspar
A
Light pink White streak Vitreous 2 good cleavages @ 90° Irregular fracture 6-6.5 Diag: 2 cleavages Where found: granite
4
Q
Muscovite mica
A
Transparent to silvery white White streak Vitreous/ submetallic 1 cleavage perfect @180° Diag: cleavage and colour Where: metamorphic rock
5
Q
Biotite Mica
A
Transparent to brownish black Greyish streak Vitreous to sub metallic 1 perfect cleavage @180° Irregular fracture 2.5 Diag: colour and cleavage
6
Q
Hornblende (amphibole)
A
Brownish greenish black Pale grey white streak Vitreous 2 good cleavages @ 124 & 56° Irregular fracture 5-5.5 Diag: cleavage + color Found? Intrusive igneous rocks like granite or diorite
7
Q
Flourite
A
Clear green, purple White streak Vitreous 4 perfect cleavages octahedral Irregular 4 Fluorecent under UV Diag: cleavage Found? Late crystallizing mineral in felsic igneous rocks, usually through hydrothermal activity. Vein deposit, limestones
8
Q
Pyrite
A
Yellow gold Greenish black streak Metallic No cleavage Irregular fracture 6-6.5 Diag: colour and streak Found? Sedimentary rocks in O2 poor env. Like coal or black shale
9
Q
Magnetite
A
Black to reddish brown Black streak Dull-earthy-sub metallic No cleavage Irregular fracture 5.5-6.5 Magnetic Diag: magnetism Found? In igneous, meta, and sed rocks
10
Q
Haematite
A
Silvery grey Reddish brown streak Metallic No cleavage Irregular to sub conchoidal fracture Diag: colour of streak and lustre Found? Accessory minerals in igneous rocks
11
Q
Olivine
A
Bright glassy green No streak Vitreous Conchoidal fracture No cleavage 6.5-7.5 Translucent Diag: green translucent colour and fracture
12
Q
Garnet
A
Dark reddish brown White streak Vitreous No cleavage Conchoidal to uneven fracture 6.5-7.5 Diag: dark red colour + fracture Found: metamorphic rocks, can also be found in granite or basalt
13
Q
Calcite
A
White White streak Vitreous to waxy 3 perfect cleavages @ 74° Irregular fraction 3 Effervesces w HCl Diag: effervesces + cleavages Found: sedimentary rocks, like limestone, also in hydrothermal veins and hot spring deposit
14
Q
Gypsum
A
Waxy white White streak Waxy 3 poor rhombohedral cleavages Irregular fracture 2 May be fibrous Daig: waxy, scratched by finer Found: in thick layers in shale
15
Q
Orthoclase
A
White, slightly pinkish White streak Vitreous 2 cleavages @ 90° one good one perfect Uneven fracture 6 Diag: cleavage + color Found? Found in intrusive igneous rocks like granite
16
Q
Arsenopyrite
A
Silver white to grey Dark gray streak Metallic One cleavage plane Uneven fracture 5.5-6 Diag: colour Found? In ore veins that were formed at high temperature
17
Q
Chalcopyrite
A
Brassy yellow to red Green streak Metallic 2 poor cleavage plane Irregular uneven 3.5 Diag: lustre and colour Found? Forms by magmatic segregation, stratified rocks of a magma chamber. Also is pegmatite dikes
18
Q
Halite
A
White White streak Vitreous 3 perfect cleavages @ 90° 2.5 Conchoidal fracture Salty Diag: salty + cleavages Found? Sedimentary rocks found at enclosed lakes or restricted seas
19
Q
Tourmaline
A
Black White streak Vitreous Uneven fracture 7-7.5 Spars, 2 perfect cleavages Diag: cleavage Found? Granite pegmaties and also metamorphic rocks
20
Q
Kyanite
A
Light blue to white White streak Vitreous Hackly fracture 2 cleavages, one perfect one imperfect @ 79° 5 Diag: colour and cleavage Found? Found in Al rich metamorphic pegmatites + sedimentary rocks
21
Q
Andalusite
A
Brown and black White streak Vitreous 2 cleavages @ 75°, one good one poor Uneven to subconcoidal fracture 6.5-7.5 Diag: colour and cleavage Found? Metamorphic minerals which are formed under low pressure and low to high temp. Like schist or gneiss
22
Q
Stauralite
A
Brownish black Pale brown Dull and earthy No cleavage Uneven fracture 7-7.5 Twinning Diag: twinning Found: when shake is altered by regional metamorphism
23
Q
Graphite
A
Grey
24
Q
Lepidolite
A
Light purple White streak Vitreous One perfect cleavage Uneven fracture 2.5-3 Diag: cleavage and colour Found? High temperature quartz veins and granite
25
Q
Malachite
A
Bright green Green streak Dull to earthy Hackly fracture 5.5 Diag: colour and fracture Found in: carbonate rocks
26
Q
Azurite
A
Bright blue Blue streak Chalky 3 cleavage planes 1perfect, 1 fair, 1 poor Conchoidal 3.5-4 Daig: colour Found in: usually in a volcanic host rock
27
Q
Molybdenite
A
Silver grey Dark grey streak Metallic One perfect cleavage Uneven fracture 1-2 Diag: cleavage and lustre Found in high temperature, hydrothermal ore deposits
28
Q
Geothite
A
Orange, brown and black Brownies black streak Dull and earthy Uneven fracture to splintery One perfect cleavage 5-5.5 Weakly magnetic Diag: magnetic, streak Found: forms by weathering of iron oxides, sulphides, etc
29
Q
Chlorite
A
Greenish grey Light green streak Pearly to dull One perfect cleavage Splintery fracture 2-2.5 Diag: fracture and streak Found: low grade metamorphic rocks and altered igneous rocks
