How to Know Minerals
-
Upload
blaze-davis -
Category
Documents
-
view
42 -
download
1
description
Transcript of How to Know Minerals
How to Know MineralsChapter 4 Earth Science Book
read pages 46-57restate & answer Topic Questions 1-9
practice the 30 lab mineral samples
common minerals that make up the Earth’s crustRock-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 47-48 Earth Textbook
*Color*Luster
*Crystal System (shape)
ColorTopic 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 similar3. colors change/react in air
LusterTopic 2: Page 47 Earth Textbook
* Metallic Luster
* Nonmetallic Luster
the way a mineral shines
Metallic LusterTopic 2: Page 47 Earth Textbook
*shines like polished metal
*(galena, pyrite, chalcopyrite)
Nonmetallic LusterTopic 2: Page 47-48 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 47-48 Earth Textbook
*cubic – all 90º, all lengths equal*orthorhombic – all 90º, no lengths equal
*triclinic – none @ 90º*tetragonal – all 90º, some lengths equal
*monoclinic – some @ 90º*hexagonal – 3 axes @ 60º
Identification by Simple Tests
Topic 3: Page 48-50 Earth Textbook
*Streak*Fracture or Cleavage
*Hardness
StreakTopic 3: Page 48 Earth Textbook
* rub mineral on unglazed white tilemetallic - streak dark as mineralnonmetallic - streak colorless to light
the color of a mineral’s powder
CleavageTopic 3: Page 49 Earth Textbook
1 direction – micas, gypsum, talc2 directions – feldspars, hornblende3 directions – galena, halite, calcite
minerals split along flat surfaces
FractureTopic 3: Page 49 Earth Textbook
•concoidal fractures – shell-like fracture•fiberous or splintery – jagged and sharp•uneven or irregular – rough surface
minerals break along non-cleavage surfaces
HardnessTopic 3: Page 49-50 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 GravityTopic 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 CO2 Acid Test
Topic 5: Page 51 Earth Textbook
*calcite is calcium carbonate, CaCo3
*dolomite - CaMg(CO3) must be powdered*malachite & azurite are copper carbonates
*calcium carbonate fizzes in acid (HCl)
*limestone & marble calcite
Special PropertiesTopic 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 53-54 Earth Textbook
a) quartzb) feldspars: orthoclase, plageoclasec) micas: muscovite, biotite(black)d) talc
silicates with iron and magnesium (darker)Ferromagnesian Silicates
Topic 7: Page 54-55 Earth Textbook
e) amphiboles: horneblendef) pyroxenes: augiteg) olivineh) garnetsi) kaolinite
made with carbonate group –CO3
CarbonatesTopic 8: Page 55-56 Earth Textbook
•calcite(Iceland spar), dolomite
•malachite, azurite
*Calcium Carbonates
*Copper Carbonates
a metal combines with oxygenOxides
Topic 9: Page 56-57 Earth Textbook
•hematite (reddish-brown streak)•limonite (yellow-brown streak)•magnetite
•corundum
*Iron Oxides
*Aluminum Oxides
•bauxite
a metal combines with sulfurSulfides
Topic 9: Page 56-57 Earth Textbook
•galena•pyrite•chalcopyrite•sphalerite
How to Know MineralsChapter 4 Earth Science Book
read pages 46-57restate & answer Topic Questions 1-9
practice the 30 lab mineral samples