How to Know Minerals Chapter 4 Earth Science Book read pages restate & answer Topic Questions 1-15 practice the 30 lab mineral samples

common minerals that make up the Earth’s crust Rock-Forming Minerals Topic 1:Page 47 Earth Textbook * over 2000 minerals known * most are silicates (Si + O + metals) * not always large crystals * mineralogy is the study of minerals and their properties

simple observations made by looking Identification by Inspection Topic 2:Page Earth Textbook *Color *Luster *Crystal System (shape)

Color Topic 2:Page 47 Earth Textbook * first, most easily observed * least useful when identifying minerals 1. impurities change mineral’s colors 2. mineral’s colors are similar 3. colors change/react in air

Luster Topic 2:Page 47 Earth Textbook * Metallic Luster * Nonmetallic Luster the way a mineral shines

Metallic Luster Topic 2:Page 47 Earth Textbook *shines like polished metal *(galena, pyrite, chalcopyrite)

Nonmetallic Luster Topic 2:Page Earth Textbook *vitreous – shining glass (quartz) *pearly – like a pearl (mica) *greasy, oily – (talc & graphite) *resinous – like wax (sphalerite) *dull, earthy – (kaolinite, limonite) *brilliant, adamentine – (diamond)

Crystal System (shape) Topic 2:Page Earth Textbook *cubic – all 90º, all lengths equal *orthorhombic – all 90º, no lengths equal *triclinic – 90º *tetragonal – all 90º, some lengths equal *monoclinic – 90º *hexagonal – 3 60º

Identification by Simple Tests Topic 3:Page Earth Textbook *Streak *Fracture or Cleavage *Hardness

Streak Topic 3:Page 48 Earth Textbook * rub mineral on unglazed white tile metallic - streak dark as mineral nonmetallic - streak colorless to light the color of a mineral’s powder

Cleavage Topic 3:Page 49 Earth Textbook 1 direction – micas, gypsum, talc 2 directions – feldspars, hornblende 3 directions – galena, halite, calcite minerals split along flat surfaces

Fracture Topic 3:Page 49 Earth Textbook concoidal fractures – shell-like fractrure fiberous or splintery – jagged and sharp uneven or irregular – rough surface minerals break along non-cleavage surfaces

Hardness Topic 3:Page Earth Textbook *Mohs’ Hardness Scale – page 50 in text minerals ranked on a scale of 1 to 10 need fingernail, copper, steel, glass, topaz 1 softest (talc), 7 hardest common (quartz) and 10 is the hardest of all (diamond) minerals resistance to being scratched

the ratio of the mass of a mineral to the mass of an equal volume of water Specific Gravity Topic 4:Page 50 Earth Textbook specific gravity = mass of sample in air mass lost in water nonmetals - less than 4 metals - above 5

weak acid will release bubbles of CO 2 Acid Test Topic 4:Page 50 Earth Textbook *calcite is calcium carbonate, CaCo 3 *dolomite - CaMg(CO 3 ) must be powdered *malachite & azurite are copper carbonates *calcium carbonate fizzes in acid (HCl) *limestone & marble calcite

Special Properties Topic 6:Page 51 Earth Textbook taste – halite is salty magnetic - magnetite flourescence – glows under ultraviolet light, fluorite, sphalerite, willemite phosphorescence – glows even after ultraviolet off double diffraction – calcite/Iceland par splits images into 2

made with silica tetrahedrons (light colored) Silicates Topic 7:Page Earth Textbook a) quartz b) feldspars: orthoclase, plageoclase c) micas: muscovite, biotite(black) d) talc

silicates with iron and magnesium (darker) Ferromagnesian Silicates Topic 7:Page Earth Textbook e) amphiboles: horneblende f) pyroxenes: augite g) olivine h) garnets i) kaolinite

made with carbonate group –CO 3 Carbonates Topic 8:Page Earth Textbook calcite(Iceland spar), dolomite malachite, azurite *Calcium Carbonates *Copper Carbonates

a metal combines with oxygen Oxides Topic 9:Page Earth Textbook hematite (reddish-brown streak) limonite (yellow-brown streak) magnetite corundum *Iron Oxides *Aluminum Oxides bauxite

a metal combines with sulfur Sulfides Topic 9:Page Earth Textbook galena pyrite chalcopyrite sphalerite

How to Know Minerals Chapter 4 Earth Science Book read pages restate & answer Topic Questions 1-15 practice the 30 lab mineral samples