ROCK & MINERAL
IDENTIFICATION GUIDE
ROCK & MINERAL
IDENTIFICATION GUIDE
MINERALS
Igneous Rock Aphanitic -- Porphyritic -- Phenocrysts are Plagioclase Feldspar (therefore mafic) Plagioclase Feldspar Basalt Porphyry
52
1
Index Sedimentary Sedimen tary Rocks. Rocks. 57
Metamorphic Rocks Rocks .......... .................. ........ 81
Arkose ............ .................... ........ 63, 64 Breccia .............. .......................... ............ 68 Calcareni Calc arenite te .... ........ ........ ........ ........ .... 77 Chalk ............. .......................... ................ ... 76 Chert .... ......... .......... .......... ......... .... 69, 70 Conglomera Congl omerate te .... ........ ...... 66, 67 Coquina .... ......... .......... .......... .......... ..... 78 Crystalli Cryst alline ne Limestone Limestone ... 73 Diatomit Diat omitee .... ........ ........ ........ ........ ...... .. 79 Evaporiti Evapo riticc Limestone Limestone .... 74 Flint .... ......... .......... .......... .......... ......... ...... .. 71 Graywac Gra ywacke ke .... ........ ........ ........ ........ .... 65 Limesto Lim estone ne .... ........ ......... .......... ........ ... 72 Mudstone Mudst one ..... .......... .......... ....... 58, 59 Oolitic Oolit ic Limes Limestone tone .... ........ ...... 75 Quartzz Sandstone.... Quart Sandstone.... 61, 62 Shale .... ........ ........ ......... ......... ......... ........ ... 60
Blueschistt .... Blueschis ......... .......... ......... ....... ... 90 Eclogite ............. ......................... ............ 96 Gneiss Gnei ss .... ......... .......... .......... ....... .. 92, 93 Greenschi Gree nschist st .... ........ ........ ........ ....... ... 91 Greenston Gree nstonee .... ........ ........ ........ ........ .... 95 Hornfels Hornf els .... ......... .......... .......... ......... ...... 83 Marble........................... Marble...................... ..... 82 Migmatite Migmati te............ ...................... .......... 94 Phyllite ............ .......................... .............. 95 Quartzite Quart zite .... ........ ......... ......... ......... ....... 98 Schist Schi st .... ......... .......... ......... ......... .......... ..... 89 Serpentinite .............. ................... ..... 97 Skarn........... Skarn....... ........ ...... .. 84, 85, 86 Slate ............. ........................... ................. ... 87
Igneous Rock Aphanitic -- Porphyritic -- Phenocrysts are olivine and pyroxene (therefore mafic) Olivine Pyroxene Basalt Porphyry
104
53
Mineral (Silicate -- Sheet -- Mica) Not metallic -- 1 flexible cleavage plane (sheet), light colored; white streak. Muscovite
Igneous Rock Aphanitic -- Dark colored (therefore mafic) Basalt
2
51
Index
Igneous Rock Glassy (100%) Obsidian
54
Minerals .....................1
Igneous Rocks ......... 33
Actinolite ...................... 14 Biotite ............................. 3 Calcite ................... 4, 5, 6 Chlorite ......................... 31 Corundum ..................... 23 Epidote .......................... 17 Fluorite ...................... 7, 8 Galena ........................... 24 Garnet .................... 21, 22 Graphite ........................ 15 Gypsum ......................... 29 Halite ............................ 30 Hematite ........................ 25 Hornblende ................... 10 Kyanite.......................... 16 Magnetite ...................... 26 Muscovite ....................... 2 Olivine .......................... 20 Plagioclase Feldspar ..... 13 Potassium Feldspar (K-Feldspar) ........... 12 Pyrite ............................. 27 Pyroxene ....................... 11 Quartz .................... 18, 19 Serpentine ....................... 9 Talc ............................... 28
Andesite ........................ 49 Andesite Porphyry (Hornblende) .......... 50 Basalt ............................ 51 Basalt Porphyry (Olivine & Pyroxene) ................ 53 Basalt Porphyry (Plagioclase Feldspar) ............... 52 Diorite ........................... 40 Gabbro ............ 41, 42, 43 Granite ................... 37, 38 Granite Pegmatite ......... 39 Obsidian ........................ 54 Peridotite ............... 44, 46 Periodotite .................... 45 Pumice .......................... 55 Rhyolite Porphyry (K-Feldspar & Quartz) .................... 47 Rhyolite Porphyry (K-Feldspar) ........... 48 Scoria ............................ 34 Volcanic Tuff ......... 35, 36
103
Igneous Rock Aphanitic -- Porphyritic -- Phenocrysts are K-Feldspar (therefore Felsic) K-Feldspar Rhyolite Porphyry
Mineral (Carbonate) Not metallic -- Bubbles in HCL. Double refraction (2 images visible through clear sample). Rhombs, 3 cleavage planes (not 90), H=3. Calcite CaCO3
48
5
SEDIMENTARY ROCKS 0 0 1
57
Mineral (Carbonate) Not metallic -- Bubbles in HCL. Double refraction (2 images visible through clear sample). Rhombs, 3 cleavage planes (not 90), H=3. Calcite CaCO3
Igneous Rock Aphanitic -- Porphyritic -- Phenocrysts are K-Feldspar and Quartz (therefore Felsic) K-Feldspar & Quartz Rhyolite Porphyry
6
Sedimentary Rock Detrital Clastic -- Mud-sized grains - NOT white -- doesn't break in layers Mudstone
58
47
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Igneous Rock Phaneritic -- Olivine & pyroxene (therefore Ultramafic) Peridotite
46
Metamorphic Rock Not foliated -- 100% Quartz (no reaction with acid) Parent rock: Chert (including Flint and Diatomite), Quartz Sandstone Setting: Low to High grade BRSC Quartzite 98
Mineral (Halide) Not metallic -- Cubic or octahedral form. 4 directions of cleavage. Fluorite
7
Sedimentary Rock Detrital Clastic -- Mud-sized grains - NOT white -- doesn't break in layers Mudstone
59
Mineral (Halide) Not metallic -- Cubic or octahedral form. 4 directions of cleavage. Fluorite
8
Sedimentary Rock Detrital Clastic -- Mud-sized grains - NOT white -- breaks in layers Shale
60
Igneous Rock Phaneritic -- Olivine (therefore Ultramafic) Periodotite
45
Metamorphic Rock Weakly foliated -- Mottled green color -Can have slickensides -- Smooth -- Harder than fingernail (not talc or soapstone) Parent rock: Mantle rock (Peridotite) Setting: High grade H Serpentinite 97
Igneous Rock Phaneritic -- Olivine (therefore Ultramafic) Peridotite
44
Metamorphic Rock Weakly foliated -- Actinolite background with scattered garnets and kyanite Parent rock: Basalt -- Setting: High grade S Eclogite 96
Mineral (Silicate) Not metallic -- Mottled green color. Smooth, curved surfaces. No cleavage. H>2. Serpentine
9
Sedimentary Rock Detrital Clastic -- Sand-sized grains -Grains are mostly quartz Quartz Sandstone
61
Mineral (Silicate -- Double Chain -- Amphibole) Not metallic -- H=5.5. Dark green or black. 2 cleavages at 60 & 120. Splintery fracture. Long prisms. Hornblende 10
Sedimentary Rock Detrital Clastic -- Sand-sized grains -Grains are mostly quartz Quartz Sandstone
62
Igneous Rock Phaneritic -- Plagioclase Feldspar, Pyroxene (therefore Mafic) Gabbro
43
Metamorphic Rock Weakly or not foliated -- Crystals too small to see -- Green colored -- Dull Parent rock: Basalt Setting: Low grade BRS Greenstone 95
Igneous Rock Phaneritic -- Plagioclase Feldspar, Pyroxene (therefore Mafic) Gabbro
42
Metamorphic Rock Foliation: Migmatitic Texture Parent rock: Shale/Mudstone (via Slate and Phyllite and Schist and Gneiss) OR Granite (via Gneiss) Setting: Very High grade BRS Migmatite 94
Mineral (Silicate -- Single Chain) Not metallic -- H=5.5. Dark green or black. 2 cleavages at 90. (Looks like HB.) Pyroxene
11
Sedimentary Rock Detrital Clastic -- Sand-sized grains -- Grains contain a significant amount of K-Feldspar Arkose
63
Mineral (Silicate -- Framework) Not metallic -- Subparallel exsolution lamellae. 2 cleavages at 90. Pink or white color. H = 6. No twinning. Potassium Feldspar (K-Feldspar) 12
Sedimentary Rock Detrital Clastic -- Sand-sized grains -- Grains contain a significant amount of K-Feldspar Arkose
64
Igneous Rock Phaneritic -- Plagioclase Feldspar, Pyroxene (therefore Mafic) Gabbro
41
Metamorphic Rock Foliation: Gneissic Texture Parent rock: Shale/Mudstone (via Slate and Phyllite and Schist) OR Granite Setting: High grade BRS Gneiss 93
Igneous Rock Phaneritic -- Plagioclase Feldspar, Hornblende, Biotite (therefore Intermediate) Diorite
40
Metamorphic Rock Foliation: Gneissic Texture Parent rock: Shale/Mudstone (via Slate and Phyllite and Schist) OR Granite Setting: High grade BRS Gneiss 92
Mineral (Silicate -- Framework) Not metallic -- Twinning. 2 cleavages at 90. H = 6. Plagioclase Feldspar
13
Sedimentary Rock Detrital Clastic -- Sand-sized grains -Grains are mostly rock fragments Graywacke
65
Mineral (Silicate -- Double Chain -- Amphibole) Not metallic -- Green, thin needles. Actinolite
14
Sedimentary rock Detrital Clastic -- Gravel-sized, rounded grains Grains are a mixture of rock fragments and minerals Conglomerate 66
Igneous Rock Phaneritic -- Pegmatitic -- K-Felspar, Quartz, Muscovite (therefore Felsic) Granite Pegmatite
39
Metamorphic Rock Foliation: Schistose -- 100% visible crystals -Actinolite Parent rock: Basalt (via Greenstone) Setting: Med grade BR Greenschist 91
Igneous Rock Phaneritic -- K-Feldspar, Quartz, Biotite, Muscovite, Hornblende (therefore felsic) Granite
38
Metamorphic Rock Foliation: Schistose -- 100% visible crystals -Blue (Glauophane) Parent rock: Basalt (via Greenstone) Setting: Med grade S Blueschist 90
Mineral (Native Element) Metallic -- H=1. Greasy. Dark grey streak. Graphite
15
Sedimentary Rock Detrital Clastic -- Gravel-sized, rounded grains Grains are a mixture of rock fragments and minerals Conglomerate 67
Mineral (Silicate) Not metallic -- Blue, flexible blades. Kyanite
16
Sedimentary Rock Detrital Clastic -- Gravel-sized, angular grains -Grains are a mixture of rock fragments and minerals Breccia 68
Igneous Rock Phaneritic -- Quartz, K-Feldspar, Muscovite, Biotite (therefore Felsic) Granite
37
Metamorphic Rock Foliation: Schistose -- 100% visible crystals -Micas Parent rock: Shale/Mudstone (via Slate and Phyllite) Setting: Med grade BRS Schist 89
Igneous Rock Pyroclastic Volcanic Tuff
Mineral (Silicate -- Single Chain) Not metallic -- H=7. Green. Striated crystal faces. Massive. Epidote
36
Metamorphic Rock Foliation: Phyllitic Texture A few, isolated visible crystals -- Silky luster Parent rock: Shale/Mudstone (via Slate) Setting: Low-Med grade BRS Phyllite 88
17
Sedimentary Rock Chemical -- 100% Quartz composition (doesn't react with acid) Chert
69
Mineral (Silicate -- Framework) Not metallic -- Glassy, conchoidal fracture, H=7. Hex. prism with pointed end. Quartz SiO4
18
Sedimentary Rock Chemical -- 100% Quartz composition (doesn't react with acid) Chert
70
Igneous Rock Pyroclastic Volcanic Tuff
35
Metamorphic Rock Foliation: Slaty Cleavage -- No visible crystals Parent rock: Shale/Mudstone Setting: Low grade BRS Slate 87
Igneous Rock Frothy -- Dark colored (therefore mafic) Scoria
34
Metamorphic Rock Not foliated -- Calcite, Garnet, Wollastonite Parent rock: Mudstone, Sandstone, Conglomerate, Breccia (as long as contains mixture of minerals) Setting: Low to High grade C Skarn 86
Mineral (Silicate -- Framework) Not metallic -- Glassy, conchoidal fracture, H=7. Hex. prism with pointed end. Quartz SiO4
19
Sedimentary Rock Chemical -- 100% Quartz composition (doesn't react with acid) -- Black inside -Coating of Chalk on outside Flint 71
IGNEOUS ROCKS
Mineral (Silicate -- Independent tetrahedra) Not metallic -- Green, conchoidal fracture, glassy, H=7. Usually granular. Not a hexagonal crystal. Olivine
20
Sedimentary Rock Chemical -- 100% Calcite composition (reacts with acid) Limestone
72
33
Metamorphic Rock Not foliated -- Quartz, Calcite, Garnet, Rhodochrosite Parent rock: Mudstone, Sandstone, Conglomerate, Breccia (as long as contains mixture of minerals) Setting: Low to High grade C Skarn 85
Mineral (Silicate) Not metallic -- Dodecahedron form, red (sometimes), glassy, conchoidal fracture, H=7. Garnet 32
Metamorphic Rock Not foliated -- Quartz, Calcite, Garnet, Epidote Parent rock: Mudstone, Sandstone, Conglomerate, Breccia (as long as contains mixture of minerals) Setting: Low to High grade C Skarn 84
21
Sedimentary Rock Chemical -- 100% Calcite composition (reacts with acid) -- Layers of visible crystals Crystalline Limestone
73
Mineral (Silicate) Not metallic -- Dodecahedron form, red (sometimes), glassy, conchoidal fracture, H=7. Garnet 22
Sedimentary Rock Chemical -- 100% Calcite composition (reacts with acid) -- Layers of microcrystals Evaporitic Limestone
74
Mineral (Silicate -- Sheet) Not metallic -- Green, nonflexible sheets. Very small flakes. Chlorite
31
Metamorphic Rock Not foliated -- 100% Dark Composition (crystals not visible) Parent rock: Mudstone or Basalt Setting: Low to High grade C Hornfels 83
Mineral (Halide) Not metallic -- Salty taste. H=2.5. Cubic form and cleavage. Halite
30
Metamorphic Rock Not foliated -- 100% Calcite (reaction with acid) Parent rock: Limestone (including Coquina, Calcarenite, and Chalk) Setting: Low to High grade BRSC Marble 82
Mineral (Oxide) Not metallic -- H=9. Barrel-shaped, flat-end hexagons. Corundum
23
Sedimentary Rock Chemical -- 100% Calcite composition (reacts with acid) -- Made of tiny beads Oolitic Limestone
75
Mineral (Sulfide) Metallic -- H=2.5 -- SG=8! Silver cubes (form and cleavage). Galena
24
Mineral (Sulfate) Not metallic -- H=2. 1 cleavage plane. Translucent. Gypsum
29
METAMORPHIC ROCKS
Sedimentary Rock Organic Clastic -- 100% Calcite composition (white -- reacts with acid) -- Mud-sized shells Chalk
76
81
Mineral (Silicate -- Sheet) Not metallic -- H=1. Feels greasy or soapy. Opaque. Not metallic. Talc
28
Mineral (Oxide) Metallic & Nonmetallic -- Red streak. Rust. Hematite
25
Sedimentary Rock Organic Clastic -- 100% Calcite composition (reacts with acid) -- Sand-sized shells Calcarenite
80
77
Mineral (Oxide) Metallic -- Attracted to a magnet. SG=5.2. No cleavage. Magnetite
26
Sedimentary Rock Organic Clastic -- 100% Calcite composition (reacts with acid) -- Gravel-sized shells Coquina
78
Mineral (Sulfide) Metallic -- Cubic form, brassy color, and SG=5. Pyrite
27
Sedimentary Rock Organic Clastic -- 100% Quartz composition (white -- doesn't react with acid) -Mud-sized shells Diatomite 79
