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Mar 25 2013

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Minerals and rocks from GLGY311 Lab

A better images of minerals can be found here

The following images are taken from a Samsung S III phone (Yes, you can’t believe the quality of detail on these images came from a 8 pix camera; contact me for technical/electronics detail on that) during the lab periods for Geology 311 (Mineralogy and Rocks) Winter 2013 at the University of Calgary.

Beautiful example of dolomite habit.

Beautiful example of dolomite habit.

Please click on the image on the left to access the larger original file.
Download the PDF Version here.

Igneous and Precipitate Minerals and Rocks

Sample Properties
min311btxpl
min311btxpl2
min311btxplh
min311biotite
min311biotite

Biotite

Chem: K(Fe,Mg)3AlSi3O10(OH)2
Type: Sheet / Phyllosiclicate
Structure: T-O-T+c structure
Comp. Anio: (Si4O10)4-
Si-to-O: 2 ; 5
Cry. sys: Monoclinic
Hd: 2.5 / 3.0
Hs: shiny black
Col/pleo: tan/straw brown – dark brown or green – brown green
Relief: moderate/+ve
Cleve: perfect cleavage
Twin: none
Habit: massive/platy
Ext: parallel / pebbly
Int. col: 3rd – 4th
Other: vitrous

min311calppl
min311calxplmin311calcite

Calcite

Chem: CaCO3
Type: rhombohedral / trigonal
Hd: 3
Hs: Colourless, white, grey colourless, maybe dirty
Relief: high/positive
Cleve: brittle / concoidal black with pastel stripes
Twin: wiggly twins?!?
Habit: crystalline/granular
Ext: twinkling extinction
Int. Col: VERY HIGH – 4th order
Other: reacts readily with HCl

min311chromitexpl

Chromite (alt)

Chem: FeCr2O4
Hs: brown streak, metallic luster, black granular
Other: black under both xpl and ppl

min311grtppl
min311grtxpl

Garnet

(Ca,Fe,Mg,Mn)3Al2Si3O12
Orthosilicate / Nesosilicate
T-O structure
Comp. An: SiO44-
Si-to-O: 1 ; 4
Type: isometric / cubic
Hd: 6.5 – 7
Hs: red but variety too
Col/pleo: clear/dirty – none
Relief: high/positive
Twin: none/uneven
Habit: blocky/cubic
Ext: NA

min311hblxpl
Lick here
Lick here
min311hblppl
Lick here
min311hblxpl2
min311hbppl2
min311rockWhbl

Hornblende(type of amp)

Chem: Ca2(Mg,Fe,Al)5(Al,Si)8O22(OH)2
Type: Double Chain / Insolcate
Structure: T-O-T structure
Comp. Anio: (Si4O11)6-
Si-to-O: 4 ; 11
Cry. sys: Monoclinic
Hd: 5.0 – 6.0
Hs: shiny black – underlaying green?
Col/pleo: green-brown/light-darker
Relief: high/positive
Cleve: brittle – 2@60/120
Twin: simple twins (sometimes)
Habit: bladed / fibrous
Ext: inclined (14-25)
Int. col: 2nd low – 3rd high?
Other: dark opaque rim

min311kfelppl
min311kfelxpl
Under XPL.
min311kfelxpl2
min311granite

K-Feldspar
(Orthoclase)

Chem: KAlSi3O8
Type: Framework / Tectosilicate
Comp. Anio: SiO2
Si-to-O: 1;2
Cry: Monoclinic
Hd: 6
Col/pleo: perthitic texture in pink-white
Relief: very low/-ve
Clev: 2@90
Twin: tarten/carlsbad
Habit: tabular
Int. col: 1st – grey/white

min311olvxpl
min311olvxpl2
min311olvxplext
min311olvppl
min311olv_px_chrmxpl
min311olv_px_chrmppl
min311olv_thin
min311olivine

Olivine

Chem: (Fe,Mg)SiO4
Type: Orthosilicate / Nesosilicate
Comp. Anio: SiO44-
Si-to-O: 1 ; 4
Cry. sys: orthorhombic
Hd: 6.5 – 7
Hs: yellow-green/olive green
Col/pleo: colourless-olive green/none
Relief: high/positive
Cleve: none/irregular
Habit: granular
Ext. parallel to crystal faces
Int. col: 2nd – 4th
Other: rarely with quartz

min311orthoxpl
min311orthoxplExt

Orthopyroxene

Chem:(Fe,Mg)2Si2O6
Type: Single Chain / Inosilcate
TOT: T-O-T structure
Comp. An: (SiO3)2-
Si-O: 1 ; 3
orthorhombic
Hd: 5.0 – 7
shiny black – dull
weathered black pale green – pink
Relief: moderate/+ve
Cleve: 2@90
Habit: thin lamellar tabular parallel
Int. Col.: 2nd – brown/yellow

min311plg2
min311plg
min311plgxpl_zone
thin section

Plagioclase

Chem: (Ca,Na)AlSi3O8
Type: Framework / Tectosilicate
Comp. anio: SiO2
Si-to-O: 1 ; 2
Cry. sys: Triclinic
Hd: 6 – 6.5
Hs: grey – white
Col/pleo: clear/dirty
Relief: low/-ve
Cleve: 2@90
Twin: albite/carlsbad/zone
Habit: tabular
Int. col: 1st – grey/white
Other: zoning – Na rich rim / Ca rich core
NOTE zoning in the last petrographic image.

min311qtppl
min311qtppl2
Taken under PPL.
min311qtpplcrymin311quartz
min311quartz2

Quartz

Chem: SiO2
Type: Framework / Tectosilicate
Comp. Anio: SiO2
Si-to-O: 1 ; 2
Cry. sys: rhombohedral / trigonal
Hd: 7
Hs: many colours
Col/pleo: translucide clear/none
Relief: low/negative
Cleve: none/concoidal
Twin: none
Habit: massive/colmnar
Ext. wavy
Int. col: 1st – grey/white

min311tourmaline

min311tourmaline2

Tourmaline

Metamorphic/Sedimentary Minerals and Rocks

Sample Properties
min311actinolite

Actinolite

Chem: Ca2(Mg,Fe)5Si8O22(OH)2
Inosilicate
Monoclinic
moderate/+ve
green under PPL

311andalusiteppl
311andalusitexpl
311andalusitexpl2
min311andalusite
min311andalusite2

Andalusite

Chem: Al2SiO5
Orthosilicate / Nesosilicate
orthorhombic
7-7.5
red? Dark cross-like in x-section = chiasolite
Col/pleo: clear/dirty – darker than Cordierite in ppl
Relief: moderate/+ve
Ext: parallel
Int. Col: 1st – grey
Other: looks like a dirtier Cordierite, higher relief LOW PRESSURE POLYMORPH

311_341bedding_cleavage

Bedding vs Cleavage

To be updated…

TBA

Blueschist

This rock is formed deep underground about ~15 to 30 km of depth with between ~200 to 500 degrees Celsius. Blue colour is caused by Glaucophane mineral in the rock, which is a type of amphibole.

min311chertppl
min311chertxpl
min311chert

Chert

Chem: SiO2
Hd: 7
Hs: black, grey, white
Col/pleo: dirty brownish grains – none
Relief: low/-ve
Cleve: none/concoidal
Habit: nodules
Int. col: 1st – grey/white
Notes: not a true mineral rather a siliceous ooze – fine crystalline in xpl. Hardness same as quartz

min311chalcedonyqt

Chalcedony and cavity filled with quartz

Chalcedony is a type of fibrous cryptocrystalline to fine grained silica that forms in pores, cavities and vugs in pre-existing rocks by precipitation from Si-rich fluids that pass through the rocks. Agate is a more brightly coloured variety of chalcedony that typically shows colour banding, with the colours being due to trace amounts of iron and manganese (or, increasingly, to dyes!). The concentrically banded geodes that you see in rock shops are vugs that have been partially to wholly filled with chalcedony/agate.

min311chloriteppl
min311chloritexpl

Chlorite

Chem: (Mg,Fe)3(Si,Al)4O10(OH)2*(Mg,Fe)3(OH)6
Sheet / Phyllosillicate
T-O-T structure
Monoclinic
Hd: 2-2.5
Hs: green clear – green
Relief: high/positive
Cleve: perfect cleavage foliated masses – 2nd – Berlin Blue
Other: has inclusions

311coal

Coal

To be updated…

min311dolomiternx

Dolomite

CaMg(CO3)2
rhombohedral / trigonal
Hd: 3.5 – 4
Hs: Colourless, white, grey (due to impurities, it can be many colours)
Col/pleo: colourless/none
Relief: low-moderate
Cleve: perfect
Twin: black with pastel stripes, wiggly twins?!?
Habit: crystalline/granular
Ext: twinkling extinction
Int. Col: VERY HIGH – 4th order
Other: Sugary texture may only be observed in finely crystalline dolomite as opposed to curved crystals faces of coarse dolomite. HCL reaction is very poor to none. It is extremely difficult to separate dolomite from calcite using a thin section. Precipitate mineral!

min311epidote
min311epidote2
min311epidote3

Epidote

Chem: FeAl2O-OH[Si2O7][SiO4]
Sorosilicate
Monoclinic
6
silver/pistachio green yellow or green
colourless to greenish yellow
Relif: high/+ve
brittle – planar
lamellar (not common) fibrous, coarse to fine granular, massive.
3rd – bright green vitrous,
Notes: pearly (Regional and contact metamorphic rocks)

311_341pressure_shadow

Garnet with pressure shadows

Please check the information for the mineral in the igneous table above.

min311he-qtppl
min311he-qtxpl
min311he-qt

Hematite (Ore) (B), Quartz (A)

On the XPL photo, you can see the radiating cement of quartz (A) and the think black-brown (to dark reddish) outline of hematite (B) Hs: red-brown streak, steel gray and metallic shiny

min311kyaniteppl
min311kyaniteppl2
min311kyanitexpl
min311kyanitexpl2
min311kyanitexpl3
311kyanite
min311kyanite2
min311kyanite3
min311kyanite4

Kyanite

Chem: Al2SiO5
Type: Triclinic
Hd: 5.5-7
Hs: blue
Col/pleo: clear
Relief: high/+ve
Twin: simple twins (sometimes)
Habit: bladed / tabular
Ext: inclined
Int. Col: 1st – grey/yellow
Other: HIGH PRESSURE POLYMORPH, may show stepped appearance like “tree-bark” in thinsection

min311mudstoneIntmudppl
min311mudstoneIntmudxpl
min311mudstoneIntmud
min311mudstoneclappl
min311mudstoneclaxpl
min311mudstonecla

Mudstone

with mud interclasts

AND

with interclasts of fragments

min311muscoppl
min311muscoxpl1
min311muscoxpl2

Muscovite

Chem: KAl3Si3O10(OH)2
Sheet / Phyllosilicate
T-O-T+c structure
Comp. An: (Si4O10)4-
2 ; 5
Monoclinic
Hd: 2.5 / 4.0
Hs: silvery/white – colourless
Col/pleo: clear/none
Relief: moderate/+ve
Cleave: perfect cleavage
Twin: none
Habit:massive/platy parallel / pebbly 2nd – 3rd vitrous

min311oolithsppl
min311oolithsStylolitesxpl

Ooids

The second image (XPL) shows with stylolites…

min311fosppl
min311fosxpl

Fossils in Packstone

to be updated…

311serprx

Serpentine

to be updated…

min311silxpl
min311silppl
min311silppl1
min311silppl2
min311silxpl2
min311silxpl3

Sillimanite

First two images are from an altered formation of the mineral in igneous rocks.

Chem: Al2SiO5
orthorhombic
Hd: 7.5
Hs: white/yellow
Col/pleo: clear/none
Relief: moderate to high/+ve
Habit: cylindrical/fibrous
Int. col: 2nd – pink

min311stauroppl
min311stauroppl1
min311stauroxpl3
min311stauroxpl1
min311stauroxpl2
min311stauroxpl3
min311staurolite1min311staurolite2

Staurolite

Chem: (Fe,Mg,Zn)2Al9(Si,Al)4O20(OH)4
Type: Orthosilicate / Nesosilicate
Monoclinic
Hd: 7-7.5
Hs: dark brown / black
Col/pleo: honey/potato yellow – none (ppl)
Relief: high/+ve
Cleve: subconcoidal
Ext: zoning?
Habit: intersecting prisms like a cross
Int. Col: 2nd – mid/high yellow
Other: poikiloblastic (air bubbles), “stauros” greek for cross – 2intersecting prisms HEXAGONAL SHAPED EUHEDRAL

min311tremolite
min311tremolite2

Tremolite

Monoclinic
5.0-6.0
white, brown…
colourless – none
moderate/+ve
brittle
2@60/120
silky, fibrous
2nd – bright
turquoise similar to sillimanite in handsample

311zebradolrx

Zebra Dolostone

This type of rocks were originally limestone, now transformed into ‘Zebra’ dolomite.

At least partially fracture controlled, because of planar zones of coarse, light-coloured dolomite in darker, fine grained host. However, all of the rock now consists of dolomite, including the dark fine grained portions, suggesting an earlier period of pervasive dolomitization.

311hailGyp
min311hailGyp2

Halite and Gypsum

Halite is a Precipitate! Since it is white in colour, hand samples may be contaminated with other minerals causing it to appear in different coulours. The Halite is pretty much table salt, but do not taste it.

Gypsum has a sugary texture, curved crystal surfaces

To be updated…
Glass
311_rx_ObsidianGlass311_rx_ObsidianGlass_2

List of Minerals Properties To Be Updated

Please read what PPL and XPL.

Clinopyroxene Ca(Fe,Mg)Si2O6 Single Chain / Inosilcate T-O-T structure (SiO3)2- 1 ; 3 Monoclinic 5.0 – 7 shiny black – dull weathered black earthy/brown – nonpleochroic moderate/+ve 2@90 sometimes carlsbad / zoning thin lamellar tabular inclined (35-48) 2nd – low/mid

Apatite Ca5(PO4)3(F,Cl,OH) – – – – Hexagonal 5 very small usually – never see clear/none high/positive none/concoidal none six sided euhedral – 1st – grey/white usually a captured/ looks standing up… looks like quartz but really small

Tourmaline Na(Fe,Mg)3Al6(BO3)3(Si6O18)(OH)4 Ring / Cyclosilicate – Si6O1812- 1 ; 3 rhombohedral / trigonal 7 black hexagonal prisms seen in class? variable – variable moderate/+ve none none striated prism parallel 1st – 2nd – moderate

Cordierite Al2SiO5 Ring / Cyclosilicate orthorhombic 7-7.5 clear/dirty – lighter than Andalusite, has border moderate/+ve subconcoidal sector twinning 1st – grey/white looks like a cleaner andalusite, has patchy domains that extinct at different angles within crystal, has sometimes brown outlined border around crystal

Glaucophane Double Chain / Insolcate Monoclinic 5.0 – 6.0 grey/lavender blue lavender blue to striking blue (ppl) bladed / fibrous 3rd – bright blue

titanite pale brown – none v. high/ +ve

phlogopite

lawsonite mod. High relief

—OLD DATA–

Staurolite: pleochroic (light -dark yellow), cruciform,+

Andalusite: 2 @ 90, inclusion of other minerals, high relief, cloudy in PPL.

Cordierite: blobby/blocky, low interference, other minerals inclusion. And/cord look like quartz.

Silimanite: hand elongated, white bladed, thin pleochroic (yellow-orange), second order, high relief.

Chlorite: green under PPL. Purple/brown under XPL.

Clinopyroxene: higher birefringence and non-parallel extinction.

Epidote: “stain glass” yellow-green-blue under XPL. hand s vitreous.

Glaucophane: blue amphibole found in blueschists.

Tremolite: white in PPL, found in calcitic rocks only.

Permanent link to this article: http://sanuja.com/blog/minerals-from-glgy311-lab

1 ping

  1. Rocks through a lense » Sanuja Senanayake

    […] All of the following images are taken using Samsung Galaxy S III camera with 8.0 MP resolution. The rocks have a dominant mineral(s); indicated in caption. Some additional images may be found here. […]

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