Quartz
Milky white (or clear or pink or prpl) White streak No cleavage Conchoidal 7 Diag: fracture Found in granite
Oligoclase (plagioclase feldspar)
Creamy beige White streak Vitreous 2 good cleavage @ 90° Irregular fracture 6-6.5 Diag: cleavages
Microcline K/alkali feldspar
Light pink White streak Vitreous 2 good cleavages @ 90° Irregular fracture 6-6.5 Diag: 2 cleavages Where found: granite
Muscovite mica
Transparent to silvery white White streak Vitreous/ submetallic 1 cleavage perfect @180° Diag: cleavage and colour Where: metamorphic rock
Biotite Mica
Transparent to brownish black Greyish streak Vitreous to sub metallic 1 perfect cleavage @180° Irregular fracture 2.5 Diag: colour and cleavage
Hornblende (amphibole)
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
Flourite
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
Pyrite
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
Magnetite
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
Haematite
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
Olivine
Bright glassy green No streak Vitreous Conchoidal fracture No cleavage 6.5-7.5 Translucent Diag: green translucent colour and fracture
Garnet
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
Calcite
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
Gypsum
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
Orthoclase
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
Arsenopyrite
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
Chalcopyrite
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
Halite
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
Tourmaline
Black White streak Vitreous Uneven fracture 7-7.5 Spars, 2 perfect cleavages Diag: cleavage Found? Granite pegmaties and also metamorphic rocks
Kyanite
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
Andalusite
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
Stauralite
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
Graphite
Grey
Lepidolite
Light purple White streak Vitreous One perfect cleavage Uneven fracture 2.5-3 Diag: cleavage and colour Found? High temperature quartz veins and granite