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Mineral & Rock

Mineral & Rock. Composition of the Earth. Element. An element is a substance that cannot be separated into simpler substances by ordinary chemical means. The smallest part of an element that has all the properties of that element is an atom. Mineral. A mineral is a naturally occurring

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Mineral & Rock

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  1. Mineral & Rock

  2. Composition of the Earth

  3. Element • An element is a substance that cannot be separated into simpler substances by ordinary chemical means. • The smallest part of an element that has all the properties of that element is an atom.

  4. Mineral • A mineral is a naturally occurring • inorganic • solid • definite chemical composition • crystal structure. **It must have all five of the characteristics described in this definition.**

  5. Rocks • A rock is a hard substance composed of one or more minerals. • A rock can also be made of or contain naturally occurring substances that do not perfectly fit the definition of a mineral. • Rocks can be composed of volcanic glass or of opal. Both of these substances lack a crystalline structure.

  6. Rocks • หินออบซีเดียน (Obsidian) • SiO2ที่มีมลทินสูง(impurities)

  7. Bonding • Ionic bond • Covalent bond • Metal bond

  8. Lattices • Atoms in crystals form a repeating pattern called a Lattice

  9. Identifying Minerals Color -Sometimes Distinctive • Often Unreliable • Affected By: • Chemical Impurities • Surface Coating • Grain Size • Weathering Fluorite

  10. Identifying Minerals (Continued) We Need Properties Directly Linked to Atomic Structure: • Hardness • Streak • Density • Luster • Cleavage • Crystal Form

  11. สีผงละเอียด (Streak) ขีดบนแผ่นกระเบื้องที่ไม่เคลือบ หรือ แผ่นขูดสี (streak plate) สีน้ำตาลแดง สีขาว ทัลก์ ฟลูออไรต์ แร่ฮีมาไทต์ สีดำ สีเหลือง แคลโคไพไรต์ ไพโรลูไซต์ ซัลเฟอร์ ออร์พิเมนต์

  12. Hardness • Resistance to Scratching • Directly related to relative strength of atomic bonds • Scratch Test (Mohs) • Indentation Test(Knoop)

  13. Hardness Talc 1 6 Feldspar Gypsum 2 7 Quartz Calcite 3 8 Topaz Fluorite 4 9 Corundum Apatite 5 10 Diamond

  14. Mohs vs. Knoop Scales • Talc: very small • Gypsum, Fingernail: 30 • Calcite, Penny: 135 • Fluorite: 163 • Apatite: knife 430 • Feldspar, Glass: 560 • Quartz: 820 • Topaz: 1340 • Corundum: 2100 • Diamond: 7000

  15. Mohs and Knoop scale http://www.themeter.net/durezza_e.htm

  16. Density Aluminum: 2.7 Pyrite, Hematite, Magnetite: 5.0Galena: 7.5Iron: 7.9Copper: 9Lead: 11.4Mercury: 13.6Uranium: 19Gold: 19.3Platinum: 21.4Iridium: 22.4 (densest material on Earth)

  17. Luster • Metallic or Nonmetallic is the most important distinction • Resinous, waxy, silky, etc. are self-explanatory. • Vitreous is often used for glassy luster

  18. ความวาว (Luster) เป็นลักษณะที่สามารถพบได้บนผิวแร่เนื่องจากการตกกระทบและเกิดการสะท้อนของแสง วาวแบบอโลหะ (Non - metallic luster) วาวแบบโลหะ (Metallic luster) แสงสะท้อน แสงตกกระทบ กาลีนา วาวโลหะ ควอตซ์ วาวแก้ว

  19. แนวแตกเรียบ (Cleavage) เป็นลักษณะรอยแตกของแร่ที่เกิดขื้นในแนวระนาบเรียบเนื่องจากโครงสร้างอะตอมภายในผลึก รอยแตก แบบนี้จะขนานไปตามผิวหน้าของแร่ ไมกา ออร์โทเคลส แคลไซต์ กาลีนา ฟลูออไรต์

  20. รอยแตก (Fracture) รอยแตกของแร่ที่ไม่มีทิศทางแน่นอน และพื้นผิวรอยแตกไม่เป็นระนาบเรียบ แต่มีลักษณะต่างๆ กัน 1. รอยแตกโค้งเว้า (Conchoidal) 2. รอยแตกแบบเสี้ยน (Splintery) 3. รอยแตกหยักแหลม (Hackly) ทองแดง ควอตซ์ ยิปซัม 4. รอยแตกขรุขระ (Uneven) 5. รอยแตกเรียบ (Even) โรโดโครไซต์ คาลซิโดนี

  21. Crystal Form • Takes Luck & Practice • Well-formed crystals are uncommon • Crystal Classification is somewhat subtle • From solutions, melts, and vapors • Evaporation of solvent, cooling, reduction of pressure

  22. Precipitation of crystals from vapor

  23. The Crystal Classes

  24. Geologic Setting • Some minerals occur in all geologic settings: quartz, feldspar, pyrite • Some minerals occur mostly in sedimentary settings: calcite, dolomite • Some minerals occur mostly in igneous settings: olivine • Some minerals occur mostly in metamorphic settings: garnet, kyanite

  25. Special Properties Some minerals can be identified by special properties. • Magnetite is naturally magnetic. • Fluorite glows under ultraviolet light. • Halite tastes salty. • Sulfur smells like rotten eggs. • Calcite fizzes when hydrochloric acid is added to . • Uraninite is radioactive.

  26. Minerals By Class • Minerals can be organized, mainly according to their chemistry

  27. Minerals By Class(1) Elements Class: The Metals and their alloys and the Nonmetals. Sulfides Class: The Sulfides, the Selenides, the Tellurides, the Arsenides, the Antimonides, the Bismuthinides and the Sulfosalts. Halides Class: The Fluorides, the Chlorides and the Iodides. Oxides Class: The Oxides and the Hydroxides. Carbonates Class: The Carbonates, the Nitrates and the Borates.

  28. Minerals By Class(2) Sulfates Class: The Sulfates, the Sulfites, the Chromates, the Molybdates, the Selenates, the Selenites, the Tellurates, the Tellurites and the Tungstates (or the Wolframates). Phosphates Class: The Phosphates, the Arsenates, the Vanadates and the Antimonates. Silicates Class: The Silicates (the largest class). The Organics Class: The "Minerals" composed of organic chemicals! The Mineraloids: The "Minerals" that lack crystal structure!

  29. Major Mineral Suites Elements Metallic:Au, Ag, Cu • Not Al, Pb, Zn, Fe, etc. Nonmetallic: C - Diamond, Graphite • Sulfur

  30. Major Mineral Suites SULFIDES: Dense, Usually MetallicMany Major Ores • Pyrite FeS2 • Chalcopyrite CuFeS2 • Galena PbS • Sphalerite ZnS2 • Molybdenite MoS2 Major Cause of Acid Rain

  31. Major Mineral Suites HALIDES: Usually Soft, Often Soluble • Halite NaCl • Fluorite CaF2 SULFATES: Soft, Light Color • Gypsum CaSO4 • Barite BaSO4

  32. Major Mineral Suites OXIDES: Often Variable, Some Ores • Hematite Fe2O3 • Bauxite Al(OH) 3 (a hydroxide) • Corundum Al2O3 (Ruby, Sapphire) CARBONATES: Fizz in Acid, Give off CO2 • Calcite CaCO3 • Dolomite CaMg (CO3)2

  33. Carbonates • Principal Components of limestone and dolostone • Storehouse for CO2

  34. Oxide: Hematite

  35. Hydroxide: Bauxite

  36. Most Important Mineral Suites : The Silicate Minerals • Si + O = 75% of Crust • Silicates make up 95% + of all Rocks • SiO4: -4 charge • Link Corner-To-Corner by Sharing Oxygen atoms

  37. Silica Structures

  38. Asbestos

  39. Silicates

  40. Tectosilicates - 3-D Networks • Quartz Feldspars

  41. Quartz

  42. Reference • http://mineral.galleries.com/minerals/by_class.htm • http://www.johnbetts-fineminerals.com/jhbnyc/minname.htm • http://www.geo.sc.chula.ac.th/Knowledge/Rock%20and%20Mineral.htm

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