its related mineral . more closely related to descriptive mineralogy. definition and mineral classification based on major physical differences

1. Descriptive Mineralogy
Geol. 401 (Major/Minor)
Dr. Adnan Khan
Assistant Professor
Department of Geology
University of Karachi
Cell No. 0300-3635848

2. Mineralogy
DESCRIPTIVE
MINERALOGY CRYSTALLOGRAPHY
Dr. Adnan Khan Dr. Maria Karim

3. RECOMMENDED BOOKS
• No book is recommended as prescription.
• Any relevant book of mineralogy can be used as
reference book.
• Selected chapters compilation is available at junaid
Photoshop, Department of Physics

4. Mineralogy
Scientific discipline that is concerned with all aspects
of minerals:
1. Physical Properties
2. Chemical Composition
3. Crystal Structure
4. Occurrence and Distribution in Nature
5. Origins (physicochemical conditions of formation).

5. Mineral
 Naturally occurring
 Inorganic
 Solid
 Specific Chemical Composition
 Regular Internal Structure

6. NATURAL VS SYNTHETIC CRYSTAL

7. THE HISTORY OF MINERALOGY
• The term minera (ore) was introduced by the Italian scientist Bernard Cesi (1581-
1630 AD).
• Mineral world began with the use of stones.
• Stones were used for the most primitive tools of labor and arms.
• Stones were selected based on form, mass and strength.
• Articles made up of silicon, obsidian, chalcedony were of high quality.
• Clay was being used to manufacture pottery.

8. • Bright color stones were used for ornaments and amulets.
• Mineral paints were used for rocks and cave drawings, and
for cosmetic manufacture.
• Some stones were used in food and as medicines.
• In metal age, mining of the ores of gold, silver, copper, tin,
lead, mercury, iron and precious stones developed

9. • Bronze (alloy of Cu and Pb) and Fe were used later for
arms, labor and domestic tools.
• Limestone and sand stones were used as building
material while marble, granite, basalt and quartzite
were used for interior and exterior decoration.
• Baked clay and lead were used for manufacture of
water pipes

10. VARIETIES OF MINERALS
CHEMICAL VARIETY
• Characterized by the presence of additional elements
within certain natural boundaries.
• Sometimes they have their own names.
• E.g. Ferrous Sphalerite or Marmatite
ZnS (Zn,Fe)S

11. Marmatite Sphalerite

12. STRUCTURAL VARIETY
• Distinguished by some specific features of the crystal
structure, usually with the chemical composition
remaining constant.
• E.g. Right handed and left handed structural forms of
Quartz, Orthoclase/ Sanidine.

13. Enantiomorphism

14. MORPHOLOGICAL VARIETY
• Posses innately their own shape of individuals or mineral
aggregate. e.g.
• Chalcedony, Cryptocrystalline Quartz.
• Selenite, fibrous variety of Gypsum.
• Serpentine and asbestoses.

16. Fibrous variety crystalline variety

17. PHYSICAL VARIETY
• Characterized by specific physical properties mainly
optical, such as transparency and color.
• E.g. Colored: Beryl, Green Emerald, Blue Aquamarine,
Yellow Heliodor.
• Transparent: Quartz, brown-Citrine, colorless-Rock
Crystal, purple- Amethyst, white-Milky.

18. Emerald Aquamarine Heliodor

19. Rock crystal
Amathyst
Milky Quartz
Citrine
Pink quartz

20. Classification of the Minerals
• Native Elements (Ag, Au)
• Halides
• Sulfides
• Oxides
• Hydroxides
• Carbonates
• Sulfates
• Phosphates
Silicates (rock forming)
• – Orthosilicates
• – Sorosilicates
• – Cyclosilicates
• – Chain Silicates
• – Layer Silicates
• – Tectosilicates

21. Occurrence and Formation
The four main categories of mineral formation are:
(1) Igneous
(2) Sedimentary
(3) Metamorphic
(4)Hydrothermal

22. LOW IRON CRYSTAL HIGH IRON CRYSTAL

24. Native Elements
Fe, Co, Ni: Meteorites
Platinum Group: (Ru, Rh, Pd, Os, Ir, Pt): Mafic Igneous
Rocks
Coinage metals: Cu, Ag, Au
Cu, Ag: Supergene Enrichments (Sulfide Oxidation)
Au: Low Temperature Hydrothermal, Placer

25. Halides
Halite (NaCl) and Sylvite (KCl)
Evaporites
Fluorite (CaF2)
Low temperature hydrothermal
Cryolite (Na3AlF6):
Pegmatite

26. Sulfides

27. Fe Sulfides
Pyrite FeS2
Marcasite FeS2
Pyrrhotite Fe1-xS
Troilite FeS
Arsenopyrite FeAsS

28. Other Sulfides
• • Sphalerite ZnS
• • Molybdenite MoS2
• • Galena PbS
• • Realgar AsS and Orpiment As2S3
• • Arsenopyrite FeAsS
• • Stibnite Sb2S3
• • Cinnabar HgS

29. Simple Oxides
Hemioxides
Cuprite(Cu2O)
Ice (H2O)
Monoxides
Periclase (MgO)
Wüstite (FeO)
Manganosite
(MnO)
Lime (CaO)
Zincite (ZnO)
Bromellite (BeO)
Tenorite (CuO)
Sesquioxides
Corundum (Al2O3)
Hematite (Fe2O3)
Bixbyite (Mn2O3)
Dioxides
Rutile (TiO2)
Anatase (TiO2)
Brookite (TiO2)
Cassiterite(SnO2)
Pyrolusite(MnO2)

30. Simple Oxides

31. Hemi-Oxides (M2O)
Ice (H2O) Hexagonal
Cuprite (Cu2O)
Why not Na2O?
(Na radius too large)

32. Monoxides (MO)
Rock salt oxides MgO, FeO, MnO, CaO, NiO
Periclase MgO - Wuestite FeO
Manganosite MnO
Lime CaO
Bunsenite NiO
Zincite oxides: zincite ZnO, bromellite BeO
Other monoxides:
TenoriteCuO, MontroyditeHgO

33. Sesquioxides (M2O3)
A sesquioxide is an oxide containing three atoms of oxygen with two
atoms of another element.
Corundum Group
Corundum Al2O3
Hematite Fe2O3
Karelianite V2O3 and Eskolaite Cr2O3
Other Sesquioxides
• – Bixbyite Mn2O3

34. Dioxides
Rutile Group
• – Rutile TiO2; Anatase; Brookite
• – Cassiterite SnO2
• – Pyrolusite MnO2
• – Stishovite SiO2
• • Uraninite (UO2) and Thorianite (ThO2)
• • Baddeleyite ZrO2

35. Complex Oxides
Two or more different cations
Spinel Group: M2TO4
Ilmenite Group : FeTiO3
Pseudobrookite Group : A2BO5
Perovskite Group : CaTiO3
High Pressure silicate analogues

36. Spinel Group
• • Spinel MgAl2O4
• • Hercynite FeAl2O4
• • Chromite FeCr2O4
• • Magnesiochromite MgCr2O4
• • Magnetite Fe2+Fe3+2O4
• • Magnesioferrite MgFe2O4
• • Gahnite ZnAl2O4
• • Ulvospinel TiFe2O4
• • Ringwoodite Mg2SiO4

37. Ilmenite Group
• • Ilmenite FeTiO3
• • Geikielite MgTiO3
• • MgSiO3

38. Pseudobrookite Group
Pseudobrookite Fe2+Ti2O5
Ferro-pseudobrookite TiFe3+2O5
Armalcolite (Mg,Fe2+)Ti2O5

39. Perovskite
Perovskite CaTiO3
MgSiO3 (Lower mantle phase)

40. Hydroxides
• • Brucite Mg(OH)2
• • Gibbsite Al(OH)3
• • Boehmite and Diaspore AlO(OH)
• • Bauxite (Mixed Al hydroxides)
• • Goethite FeO(OH) (+Lepidochrosite)
• • Limonite Fe(OH)3

41. Carbonates
Calcite Group
Aragonite Group
Dolomite Group
Other carbonates

42. Calcite Group
Calcite CaCO3
Magnesite MgCO3
Siderite FeCO3
Rhodochrosite MnCO3
Smithsonite ZnCO3

43. Aragonite Group
• • Aragonite CaCO3
• • Strontianite CaCO3
• • Witherite BaCO3
• • Cerussite PbCO3

44. Dolomite Group
Dolomite CaMg(CO3)2
Ankerite CaFe(CO3)2

45. Other Carbonates (+Nitrates)
• Malachite (Green) Cu2(OH)2CO3
• Azurite (Blue) Cu3(OH)2(CO3)2
• Cu1+ or Cu 2+?
• Niter KNO3
• Soda Niter NaNO3

46. Sulfates
• Gypsum CaSO4•2H2O
• Anhydrite CaSO4
• Celestite SrSO4
• Barite BaSO4
• Anglesite PbSO4
• Alunite KAl3(OH)6(SO4)2

47. Gypsum/Anhydrite
GypsumCaSO4•2H2O
Hardness 2
Evaporite Mineral
Contains molecular
water
Anhydrite CaSO4
Hardness 3-3.5
Evaporite Mineral
Contains no molecular
water

48. Celestine Barite Anglesite
SrSO4 BaSO4 PbSO4
Hydrothermal Hydrothermal Hydrothermal

49. Phosphates, Tungstates, Vanadates
Phosphates are based on P5+O4 tetrahedron.
By far the most important one is apatite.
Ca5(PO4)3(OH,F,Cl)
Tungstate and Vanadate are based on W6+O4 and V5+O4
tetrahedra.
Some are isostructural with apatite and so included in the
same group, but they are usually considered oxides.

50. Apatite Ca5(PO4)3(OH,F,Cl)
Hydroxy- Fluor-, and Chlor- apatites
Major component of teeth and bone
Common accessory mineral in igneous and metamorphic
rock.
Some sedimentary phosphates (phosphate sands).