Minerals

1. Minerals

2. Feldspar Minerals • Feldspar Minerals: group of silicates; mineral of crust, cleavage at 90 with flat, rectangular, glassy surfaces • 1. Albite ( Plagioclase): Plagioclase Feldspar: calcium to sodium rich; example is albite; has striations (thin parallel grooves) • 2. Amazonite (Microcline)   • 3. Orthoclase Group: Orthoclase Feldspar: Feldspar group; also known as potassium feldspar KAlSi3O8

3. Silicates • Mica Group: silicate; perfect cleavage; in one direction it splits into sheets; examples are muscovite (colorless or silvery); biotite (black with magnesium and iron); lepidolite (lilac or rose colored) • Amphibole group: silicate; two directions of cleavage not at 90; narrow elongated crystals; example is hornblend ( dark contains magnesium and iron) • Pyroxene group: two directions of cleavage at 90; typically dark; example is augite( dark with magnesium and iron)

4. Other Minerals • Clay mineral: Silicate; weathered feldspar; very fine grained; earthy luster; smooth; example is Kaolinite • Non-Silicate Minerals: 8% of earth’s crust; element, oxides, sulfides, etc. • Carbonates: non silicate; example is calcite (CaCO3) with limestone and marble • Halides & Sulfides: evaporate minerals

5. Classes of Silicates • Sorosilicates • Cyclosilicates • Inosilicates • Phyllosicates • Tectosilicates

6. Extra Info • Quartz or quartz crystal, a nearly pure silicon dioxide specimen occurs in most igneous and practically all metamorphic and sedimentary rocks. • Lepidolite, muscovite, and biotite exhibit cleavage with weak bonds in only one direction. • Halite is classified as an evaporite due to its having been formed by the evaporation of saline water within partially enclosed basins. • Almandine garnet is able to overpower and displace surrounding solid material during its formation so that it almost always develops its characteristic crystal faces. • Bornite or chalcopyrite, often associated with the minerals sphalerite and galena, is the main source of copper.

7. Extra Info • Sphalerite is a major source of zinc. • Hematite’s streak is always reddish brown in color in spite of its actual color being brown, red or silver. • Gold has a specific gravity of 19.3. • Feldspar is the most common mineral found in Earth’s crust. • Opal is not a crystalline solid and is, instead, classified as a mineraloid.

8. Extra Info • Galena is the primary source of lead. • Staurolite consists of a basic silicate of iron and aluminum in prismatic orthorhom- bic crystals often twinned so as to resemble a cross. • Fluorite, represented by its more rare octahedral crystal form at this station, occurs naturally in nearly every color of the spectrum. • Amazonite is a form of microcline named for a South American rainforest where it is nowhere to be found. • Ulexite’s optical effect is created by individual fibers acting as fiber-optic cables, transmitting light from one surface to the other.

9. Extra Info • Sodalite has a pleasant blue color, usually includes white veins or streaking, and is commonly used as a carving stone. • Rhodonite, a pink and red specimen, often has black manganese oxide veins running through it, giving it a distinct appearance of pink with black crisscrossing lines. • Dolomite’s crystal habits include saddle shaped rhombohedral twins and simple rhombs, some with slightly curved faces. • Beryl has several varieties, including the emerald specimen at this station.

10. What are the two most abundant elements by mass found in Earth's crust? • aluminum and iron 2. sodium and chlorine 3. calcium and carbon 4. oxygen and silicon

11. Which mineral is white or colorless, has a hardness of 2.5, and splits with cubic cleavage? calcite 2. halite 3.pyrite 4. Mica

12. Common Minerals

13. Hematite • Used for mining iron ore • Has a reddish brown streak because of the iron and oxygen present, making rust • Classified as oxide • Has higher specific gravity than corundum • Streak test would be a good test to identify; by crushing will notice blood red powder • Silver or gray in appearance • When magnetite reacts with oxygen, hematite will form • Rich source of iron • Hardeness: 5-6

14. Goethite • Used for mining iron ore • Is classified as a hydroxide

15. Limonite • Also called brown iron ore or brown hematite

16. Tremolite • Has another form, Asbestos, can be used as a fire retardant

17. Copper • Native Element/Mineral • Same hardness as bornite • Is very conductive • Is used to make the alloy, Brass

18. Bornite • Same hardness as copper • Is a copper, iron sulfide • Is an ore of copper • Used in jewelry

19. Corundum • Is the 2nd hardest natural mineral known to man • Diamond is four times harder • Used for abrasive and as a gemstone • Classified as oxide • Mineral of rubies and sapphires • Hexagonal crystal system • Hematite family • Chemical formula: Al2O3 • Hardness: 9

20. Aragonite • Carbonate mineral • Is unstable at normal temperatures at Earth’s surface • Has magnesium in its composition • Same chemical formula as calcite and therefore is polymorph of calcite • CaCO3 • Different crystalline structre than calcite; but when heated will form calcite • Softer than feldspar • Orthorhombic • Specific Gravity 2.94

21. Calcite • Carbonate mineral • Transparent variety is called Iceland spar • Primary component of cave formation • Same chemical formula as aragonite and therefore is polymorph of aragonite • Exhibits effervesce • Calcite is made by plankton and falls to bottom of sea when plankton die

22. Azurite • Copper carbonate • About same hardness as malachite • Classified as carbonate and thus related to calcite and dolomite • Classified as copper ores • Used as pigments, minor ores of copper, and ornamental • Does not effervesce in hydrochloric acid

23. Malachite • Copper carbonate • Can replace azurite over time • About same hardness as azurite • More common than azurite • classified as carbonate and thus related to calcite and dolomite • Classified as copper ores • Used as pigments, minor ores of copper, and ornamental • Will effervesce in diluted hydrochloric acid • Crystal System: Monoclinic

24. Graphite • Is primarily composed of carbon • Can conduct electricity on one plane of tetrahedrally bonded carbon atoms • Main function is lubricant • Also used in pencils, control rods of nuclear reactors, batteries • Found in China, Brazil, Canada, Madagascar, Sri Lanka • Pure Deposits in Borrowdale, England • Hexagonal crystal system

25. Silver • Native Element • The coating on the spoon • Reacts with sulfur and tarnishes • Best conductor of electricity • Crystal System: Cubic • Easily tarnished in air and is therefore rarely found in its pure form

26. Sphalerite • Is a zinc, iron sulfide • Hardness is a little harder than copper • Major ore of zinc • Is commonly found in sedimentary environments in evaporate deposits, volcanic activity • When mixed with sulfur and water produces hydrogen sulfide gas

27. Sulfur • Native Element • When mixed with sphalerite and water produces hydrogen sulfide gas • Causes acid rain • Used in pesticides, gunpowder, and fungicides • Crstal System: Orthorhombic

28. Lepidolite • Could be called a Potassium-Aluminum-Silicate • Also has a massive form and is often associated with tourmaline

29. Muscovite • Could be called a Potassium-Aluminum-Silicate • Elastic

30. Biotite • Could be called a Potassium-Aluminum-Silicate • Elastic

31. Dolomite • CaMg(CO3)2 • rhombohedral cleavage • Also known as dolomite rock • Constituent of dolostone • Form alternative of limestone with addition of magnesium • Is a double carbonate and therefore does not dissolve as rapidly or effervesce as rapidly as calcite

32. Gypsum • Classified with evaporites, CaSO4∙2H2O • Also known as rock gypsum • Used for plaster • Generally soft • Varieties include selenite (clear with rhombohedral cleavage), alabaster (fine grain and massive), satin spar (fibrous)

33. Alabaster Gypsum • Could be used to make Plaster of Paris • Has the mineral Calcium • It could be used as a fertilizer.

34. Epidote • Classified as Sorosilicate mineral

35. Olivine • Magnesium Iron Sillicate mineral • Crystal System: Orthorhombic • It could be used as an abrasive because of its hardness • It is found in many iron-nickel meteorites • Is a neosilicate • Often glassy • Exhibits conchoidal fractures • Mg and Fe rich • Most abundant in earth’s mantle

36. Quartz • Silicate mineral • Second most abundant of crust • Constituent in sandstone and quartzite • Has conchoidal fracture

37. Amethyst • Major use is for jewelry, mineral • A type of quartz

38. Kaolinite • Used for medications, paper filler; make pottery • Is white and powdery

39. Apatite • Softer than feldspar • It is part of your bone structure and makes up the teeth of all vertebrates • Used as plant fertilizers to alter taste • Main source of phosphate in world • Crystal System: hexagonal

40. Talc • Made of hydrous magnesium silicate • Used in lubricanys, baby powder,plastics, and rubber, soapstone ornaments • Crystal System: monoclinic

41. Fluorite • Belongs to group of minerals containing halogens • Harder than halite, but appearance is same • Used in iron smelting, added to water to prevent kidney disease, lenses, nonstick coatings • Has same isometric crystal system as halite • Has fluorescent properties when under UV lights • Made of Calcium Fluoride • Crystal System: cubic

42. Halite • Belongs to a group of minerals containing halogens • Would most likely be found where seas or lakes have dried up • Same isometric crystal system as fluorite • Is necessary for the human body • NaCl evaporate • Also called rock salt • Has cubic cleavage • Used to melt ice • Can be taken out of sea water or mined • Found in Germany, England, Poland and US

43. Galena • Has a structure identical to halite • An ore of lead • Classified as a sulfide • Specific gravity is about two times heavier than magnetite • Specific gravity is about 7.5 times heavier than that amount of water • Is a natural semiconductor and is used in televisions, GPS systems and telephones • First used as kohl until found to be poisonous

44. Pyrite • Has structure analogous to galena • Can be called Fools gold or Sulfide mineral • Golden or black streak • Golden yellow in color • Grows in shiny cubes • Found in Japan, Spain, US • Used in jewelry

45. Chalcopyrite • Unlike pyrite, contains copper, and is a copper iron sulfide • Leading source of copper because it is found in large quntities and distributed widely • Also called fools gold or sulfide • Found in igneous rocks

46. Magnetite • Has two forms of iron causing the electrons to transfer between the different ions • Specific gravity is about the average for metallic minerals • Classifiead as an iron oxide • Can be made into magnets • Black or metallic • Found South Africa, US, Sweden on black sand beaches

47. Mica • Black, brown, green, or violet sometimes found colorless and shiny • Breaks into smooth thin sheets • Used in paints • Found in Brazil, India, US, Madagascar • Crystal System: monoclinic • Comes from Latin word meanining shine • Flakes sparkle in schist • Very resistant to heat and very flat • Silicate