Ore Microscopy 2012
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This document provides information on the optical and physical properties of various mineral samples. It describes several key properties of minerals including their crystal form, habit, cleavage, parting, inclusions, and twinning. It also discusses their optical properties without and with an analyzer, such as color, reflectivity, bireflectance, anisotropism, and internal reflection. Finally, it presents information on various ore textures like colloform, deformation, banded iron formation, flame, oolitic, and exsolution textures.
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Ore Microscopy 2012
- 1. Tanta University Faculty of Science Department of Geology Submitted by Mohamed Mahmoud Ahmed El-Shora
- 2. • Physical Properties • Optical Properties • Crystal form • without Analyzer “morphology” • Colour • Crystal habit • Reflactivity • Cleavage • Bireflectance & • Parting Reflection pleochriosm • Inclusions • with Analyzer • Twining • Isotropism & Anisotropism • Internal Reflection
- 3. Physical Properties • Crystal form “morphology” • Crystal habit • Cleavage • Parting • Inclusions • Twining
- 4. Crystal form • Euhedral • Subhedral • Anhedral
- 5. Crystal habit • Equant • Prismatic • Fiberous (e.g) Pyrolusite • Bladed (e.g) Hematite • Oval • Rhombic (e.g) Arsenopyrite • Rounded • Colloform (e.g) Geothite • Triangular (e.g) Galena • Irregular
- 6. Cleavage • Present • Absent 1 set Covellite Presnt 2 sets Chalcopyrite 3 sets Galena
- 7. Cleavage VS Scratches • Cleavage • Scratches • •
- 8. Parting • Present “internal Reflection” marcasite • Absent
- 10. Twining • Lameller (e.g) molybdenite
- 11. Optical Properties • without Analyzer • with Analyzer • Colour • Isotropism & • Reflactivity Anisotropism • Bireflectance & • Internal Reflection Reflection pleochriosm
- 12. Optical Properties without Analyzer • Colour : “white, red, blue, brown, yellow” • Faint yellow or pale yellow • Dark or strong red • Reddish brown Pentlandite “golden Pyrite “cremic white” Covellite “ink blue” yellow” Marcasite Chalcopyrite “yellow” Galena “brase yellow” “ white”
- 13. Optical Properties without Analyzer • Reflactivity • • R= intensity of reflected light/intensity of incident light • • Described as *low ex covellite *medium ex chalcopyrite *High ex pyrite
- 14. Optical Properties without Analyzer • Bireflectance & Reflection pleochriosm • Bireflectance: • • Ex: Chalcopyrite “brase yellow to faint yellow” • Reflection pleochriosm • • Ex: Molybdenite “grewish white to white”
- 15. Optical Properties with Analyzer • Isotropism & Anisotropism • Described as: *Isotropic “cubic” • *Anisotropic (e.g) Marcasite, Stibnite (Very strong – Strong – Moderate - Low – Very low) Marcasite Stibnite
- 16. Optical Properties with Analyzer • Internal Reflection • • Present • Absent Marcasite
- 17. Ore Microscopy Sulphide Ore Minerals Minerals Oxides Minerals
- 18. Pyrite Arsenopyrite Chalcopyrite Tetrahedrite Sphalerite Pyrrhotite Galena Sulphide Minerals Pentlandite Stibnite Niccolite Covellite Bornite Marcasite Molybdenite
- 19. Pyrite • FeS2 • Cubic • Cremic white • Reflactivity: High • Isotropic Chalcopyrite “brase yellow” Pyrite “cremic white” Sphalerite “gray”
- 20. Chalcopyrite • CuFeS2 Sphalerite “gray” • Brase yellow • Tertagonal • Reflacivity: Medium • Anisotropic Chalcopyrite “brase yellow” • Two sets of Clevage • Bireflectance: Presnt Chalcopyrite “brase yellow” Pyrite “cremic white” Sphalerite “gray”
- 21. Sphalerite • (Zn,Fe) S • Cubic • Grey • Reflactivity: low • Isotropic • Two sets of clevage
- 22. Galena • PbS • Cubic • White • Reflactivity: high • Isotropic • Three sets of clevage • Habitat: Triangular pit Gange minerals
- 23. Stibnite • Sb2S3 • Orthrohombic • White • Reflactivity :high • Very strong anisotropic • Three sets of clevage • Twining may be presnt
- 24. Covellite • CuS • Hexagonal • Ink Blue • Reflactivity: low • Anisotropic • Bireflectance may be present
- 25. Marcasite • FeS2 • Orthrohombic • Yellow “Pale yellow” • Reflactivity: high • Internal Reflection • Very strong anisotropic
- 26. Molybdenite • MoS2 • Trigonal • Grewish white • Reflactivity: high • Paleochrism • Very strong anisotropic • Lameler twining • H-shape
- 27. Bornite • Cu5FeS4 • Brown-Purple-Pink- Violet • Revlictivity: low • Tetragonal • Anisotropic
- 28. Niccolite • NiAs • Hexagonal • Yellowish brown • Reflactivity: medium • Anisotropic • pink
- 29. Pentlandite • (Fe,Ni)S8 • Cubic • Isotropic • Golden yellow • Reflactivity: medium • Two sets of clevage
- 30. Pyrrhotite • Fe x-1S x • Hexagonal • Faint brown • Reflactivity: high • Anisotropic
- 31. Tetrahedrite • Cu12Sb4S13 • Cubic • Olive green-grey • Reflactivity: low • Isotropic
- 32. Arsenopyrite • FeAsS • Monoclinic • Cremic white • Reflactivity: high • Anisotropic • Rhombic shape “crystal habit”
- 33. Magnetite Pyrolusite Hematite Oxides Minerals Ilmenite Geothite Chromite
- 34. Magnetite • Fe3O4 • Cubic • Isotropic • Pale ”faint” brown • Reflactivity: medium • Crystal habit: equent • Crystal form: euhedral • Two sets of clevage • BIF (Banded Iron Formation) Hematite Magnetite white Martization
- 35. Hematite • Fe2O3 • Trigonal • Anisotropic • White • Reflactivity: high • Crystal habit: Bladed • Internal Reflaction “reddish brown” • BIF (Banded Iron Formation)
- 36. Geothite • Fe2O3.H2O • Orthrohombic • Grey • Well crystalline • Poor crystalline • Crystal habit: colloform
- 37. Chromite • FeCr2O4 • Cubic • Isotropic • White with brown tint • Reflactivity: high • Internal Reflection: brown or reddish brown • Deformation texture
- 38. Chromite
- 39. Ilmenite • FeTiO3 • Trigonal • Light "faint” Gray • Reflactivity: high • Hematite-Ilmenite exsolution tex Light gray Ilmenite White Hematite
- 40. Pyrolusite • MnO2 • Tetragonal • Faint Brown • Reflactivity: medium • Crystal Habit: Fiberous
- 41. Texture
- 42. Colloform texture • (e.g) Geothite
- 43. Deformation texture • (e.g) Chromite
- 44. Banded Iron Formation texture • (e.g) Magnetite, Hematite
- 45. Flame texture • (e.g) Pentlandite , Pyrrhotite
- 46. Oolitic Texture
- 48. Ilmenite • FeTiO3 • Trigonal • Light "faint” Gray • Reflactivity: high • Hematite-Ilmenite exsolution tex Light gray Ilmenite White Hematite
- 49. Ilmenite-magnetite exsolution texture Trellis texture
- 50. Chalcopyrite-Sphalerite exsolution texture & Emulsion texture • Chalcopyrite-Sphalerite • Emulsion texture exsolution texture • •
- 51. Chalcopyrite-Sphalerite exsolution texture & Emulsion texture
- 52. Mohamed M Elshora President of AAPG-TUSC Phone (+2)01112078926 OR (+2)01280048933 Mail : mohamed_elshora35@yahoo.com