Mineral - A naturally occurring, inorganic, homogeneous solid with a definite chemical composition and an ordered atomic arrangement. naturally occurring - materials synthesized in laboratory do not count, must be formed by natural processes in wild inorganic - not formed by organic chemistry (e.g., sugars, etc.) homogeneous solid - single substance in solid phase which cannot be physically separated into simpler compounds definite chemical composition - composition can be represented as chemical formula (e.g., NaCl), although variation in exact composition is possible (e.g., (Mg, Fe)2SiO4 ) [range in color, hardness, specific gravity] ordered atomic arrangement – repeating structure at the atomic level, which expresses as symmetry in large specimens, i.e., crystalline structure. http://www.uoregon.edu/~jrice/geol311

COLOR Quartz SiO2 Hardness = 7 Rose Quartz Smokey Citrine Amethyst Carnelian Onyx Jasper

Quartz, Corundum, Garnet CRYSTAL FORM Quartz, Corundum, Garnet Figure 3.4

HARDNESS Figure 3.9

HARDNESS Figure 3.8

Good for metallic and opaque minerals, softer than the streakplate Figure 3.7 Good for metallic and opaque minerals, softer than the streakplate

metallic Luster - quality of light reflected from mineral surface pyrite metallic silver gold

non-metallic Luster quality of light reflected from mineral surface Some minerals may be listed in both metallic and non-metallic, or in the incorrect table, i.e., limonite vitreous (glassy) pearly resinous

EFFERVESCENCE Minerals like calcite react with weak acid, dissolving the mineral and producing lots of bubbles (effervescence) Calcite: CaCO3 HCl + CaCO3 > H2O + Cl- + Ca+ + CO2 Dolomite: CaMg(CO3)2

SPECIFIC GRAVITY Mass / Volume (gm/cm3) Orthorhombic Carbonates All minerals have same structure, only cation differs Mineral Formula Cation g/cm3 Aragonite CaCO3 20 2.95 Strontianite SrCO3 38 3.76 Witherite BaCO3 56 4.29 Cerrusite PbCO3 82 6.55 Figure 3.17

MAGNETISM Magnetite ~ Attracted by a magnet Figure 3.17

CLEAVAGE Cleavage: Breaks along planes of weakness See the way light reflects back at you (I cannot see this for you). Rotate the mineral to “find” reflective surfaces. When you find a cleavage plane, rotate Figure 3.10

CLEAVAGE Figure 3.10a

CLEAVAGE Figure 3.10b

CLEAVAGE Figure 3.10c

CLEAVAGE Figure 3.10d

Figure 3.12

Quartz (Chert), Garnet, Olivine, Corundum, no cleavage but flat ends? NO CLEAVAGE – FRACTURE Quartz (Chert), Garnet, Olivine, Pyrite, Magnetite Figure 3.12a Corundum, no cleavage but flat ends?

conchoidal fracture Fig. 02.23

CLEAVAGE – 1 PLANE, EXCELLENT Figure 3.12b

Figure 3.13

Gypsum: 1 good plane, two poor planes CLEAVAGE – 2 PLANES, GOOD Figure 3.12c Gypsum: 1 good plane, two poor planes

Figure 3.15

Figure 3.12d

Figure 3.14

Figure 3.14a

Figure 3.14b

CLEAVAGE – 3 PLANES, GOOD Figure 3.12e

CLEAVAGE – 3 PLANES, GOOD Figure 3.12f

CLEAVAGE – 4 PLANES, GOOD Figure 3.12g

CLEAVAGE – 6 PLANES, GOOD Figure 3.12h

PAGE 90 Figure 3.18

PAGE 91 Figure 3.18

PAGE 93 Figure 3.21a

MULTIPLE MINERALS: Galena, Flourite UnFigure Pg101_1

ONE QUARTZ CRYSTAL, DOUBLY TERMINATED UnFigure Pg101_1b

MULTIPLE CRYSTALS: Galena, Flourite UnFigure Pg101_1c

Can scratch copper penny (H=3.5), but not glass plate (H=5.5) Fluorite Hardness =4 Can scratch copper penny (H=3.5), but not glass plate (H=5.5) Fig. 02.15c

Look at minerals: Galena, Olivine IGNEOUS ROCK, Granite, with quartz, potassium feldspar, plagioclase, biotite Randomly Oriented. Look at minerals: Galena, Olivine UnFigure Pg101_1d

Minerals Silicates quartz (crystal form, concoidal fracture, harder than glass, various colors) plagioclase feldspar (2 planes of cleavage, striations, elongate, transluscence, pleochroism) potassium feldspar (2 planes cleavage, opaque, blocky, pink?) muscovite (colorless – silver mica, 1 plane of cleavage, scratch with fingernail) biotite (black mica, 1 plane of cleavage, scratch with fingernail) augite (pyroxene, 2 planes of cleavage at right angles, black­dark green, blocky) hornblende (amphibole, 2 planes of cleavage ~60° & ~120°, black, elongate) garnet (crystal form, various colors, harder than glass, no cleavage) olivine (color, no cleavage, glassy) kaolinite (scratch with fingernail, white to gray, massive, "clay" feel)

Minerals Oxides magnetite (magnetic, black­gray streak, color, iron oxide) hematite (red­brown streak, hardness, metallic and non­metallic luster, various forms, iron oxide) limonite (color, hardness, streak, iron oxide) corundum (hardness of 9, barrel shape crystal form, parting planes not considered as cleavage) Carbonates calcite (calcium carbonate: CaCO3, 2 planes of cleavage, effervescence, softer than glass) dolomite (calcium, magnesium carbonate: CaMg(CO3)2, similar to calcite, with less, effervescence)

Minerals Other fluorite (4 planes of cleavage, various colors) halite (3 planes of cleavage, taste, pink to white or clear, salt) graphite (hardness of 1, streak on paper) pyrite (gold color, "fools gold", no cleavage, cubic crystal form, iron sulfide) galena (very heavy, 3 planes of cleavage at right angles often "stairstepped", lead sulfide) gypsum /selenite (scratch with fingernail, pink to white color to clear, 1 good and 2 poor planes of cleavage)