NAME:                                                              THE UNIVERSITY OF WESTERN ONTARIO
STUDENT #:                                                                   LONDON                     CANADA

GEOLOGY 200A - Mineralogy Test

  Give the formula, [e.g. (Mg,Fe)2Si2O6, CaAl2Si2O8/NaAlSi3O8], the name and formula, where applicable, of the end-members of any solid solution series, e.g. forsterite Mg2SiO4-fayalite Fe2SiO4, and those features such as colour, luster, cleavage, fracture, hardness, density, as well as other characteristics such as reaction to acid, magnetism, etc, that might allow you to identify the following minerals in coarse grained rocks :

Plagioclase
Formula     End member 1 Anorthite CaAl2Si2O8 End member 2 Albite NaAlSi3O8

Colour white  lustre vitreous   cleavage 2, one perfect  hardness 6  density 2.7
Other : - albite twinning; striations.

Orthoclase
Formula   KAlSi3O8

Colour pink   lustre vitreous  cleavage two perfect  hardness 6  density 2.6
Other : -  commonly twinned (bonus)

Clinopyroxene
Formula  - Ca(Mg,Fe)Si2O6   End member 1 Diopside CaMgSi2O6 End member 2 Hedenbergite CaFeSi2O6

Colour black - green  lustre vitreous  cleavage  2 at right angles  hardness 6  density 3.2
Other : -  prismatic square cross sections (bonus)

Orthopyroxene
Formula  - (Mg,Fe)2Si2O6   End member 1 Enstatite Mg2Si2O6 End member 2 Ferrosilite Fe2Si2O6

Colour Greenish yellow to bronze lustre  vitreous to pearly cleavage two at right angles   hardness 6   density 3.2
Other : -  commonly occurs with olivine and chromite (bonus)

Olivine
Formula  - (Mg,Fe)2SiO4 -  End member 1 Forsterite Mg2SiO4 End member 2 Fayalite Fe2SiO4

Colour green   lustre vitreous  cleavage none   hardness 6.5  density 3.5
Other : -  commonly granular

Ilmenite
Formula   FeTiO3

Colour black   lustre metallic  cleavage none   hardness 6  density 4-5
Other : -  may be slightly magnetic

Apatite
Formula   Ca5(PO4)3.(OH,F,Cl)

Colour light green   lustre vitreous  cleavage poor   hardness 5  density 3.2
Other : -  hexagonal prismatic

Magnetite
Formula   FeO.Fe2O3

Colour black   lustre metallic   cleavage none   hardness 6  density 5
Other : -  magnetic, octohedrons

Quartz
Formula  SiO2

Colour clear   lustre vitreous  cleavage none   hardness 7  density 2,7
Other : -  hexagonal;       conchoidal fracture

Amphibole
Formula  - Ca2(Mg,Fe)5Si 8 O22(OH)2  End member 1 Tremolite Ca2Mg5Si 8 O22(OH)2 End member 2 Actinolite Ca2Fe5Si 8 O22(OH)2

Colour black to green  lustre vitreous  cleavage 2 at 120 degrees  hardness 6  density  3-3.5
Other : -  prismatic, acicular

 Glaucophane
Formula  Na2Mg3Al2Si8O22(OH)2

Colour Lavender blue  lustre  vitreous  cleavage 1 good   hardness 6  density 3.3
Other : -  acicular

Epidote
Formula  Ca2Al3Si3O12(OH)

Colour pistachio green   lustre vitreous  cleavage 1 perfect   hardness 6   density 3.4
Other : -

Garnet
Formula  Ca(Mg,Fe)3Al2Si3O12  End member 1) Grossularite, Ca3;  End member 2) Pyrope, Mg3;  End member 3) Almandine, Fe3;
(under conditions of low temperature metamorphism there also exists end member 4 Mn3, Spessartine)

Colour red, green white  lustre vitreous  cleavage none   hardness 7  density 3.5-4
Other : -  - dodecahedral form

Mica
Formula -     End member 1 Muscovite KAl3Si3O10(OH)2      End member 2 Biotite KAl(Mg,Fe)3Si3O10(OH)2

Colour white to brown  lustre transparent  cleavage flaky   hardness 2.5  density 2.8
Other : -

Pyrite
Formula FeS2

Colour yellow   lustre metallic  cleavage poor    hardness 6-6.5  density 5
Other : - reacts with acid

Chlorite
Formula (Mg,Fe)2Al2SiO5(OH)4 - (Mg,Fe)3Al2Si3O10(OH)2

Colour green   lustre vitreous  cleavage flaky   hardness 2   density 3
Other : -

Kyanite
Formula Al2SiO5

Colour blue white   lustre vitreous   cleavage prominent   hardness 6 density 3.5
Other : -        cross fracture cleavage

Corundum
Formula Al2O3

Colour     lustre vitreous, gem  cleavage  none   hardness 9   density 4
Other : -  hexagonal barrel shaped

Calcite
Formula CaCO3

Colour transparent   lustre vitreous  cleavage 3 perfect   hardness 3   density 3
Other : - reacts with acid

Kaolinite
Formula  Al2Si2O5(OH)4

Colour white   lustre earthy  cleavage perfect   hardness 2  density 2.5
Other : -

Serpentine
Formula Mg3Si2O5(OH)4

Colour green white   lustre pearly  cleavage perfect   hardness 2.5  density 2.5
Other : -

Talc
Formula Mg3Si4O10(OH)2

Colour white   lustre greasy  cleavage perfect   hardness 1   density 2.6
Other : -