GEOLOGY Flashcards
what cleavage or fracture does quartz have?
no cleavage, conchoidal fracture (shell like)
what does quartz metamorphise into?
quartzite (non foliated)
will a nail scratch quartz, whats the hardness?
no hardness of 7
what types of rock is quartz found in
felsic to intermediate
most metamorphic rocks
what is regional metamorphism
associated with mountain building (orogenesis) and is widespread
what fracture does garnet have
conchoidal
what cleavage do micas have
1 perfect cleavage
what igneous rocks have micas
felsic such as diorite, granite, rhyolite and andesite
what cleavage does Kfs have
3 perfect cleavages at 120˚
what twinning is Kfs
simple
what colour is kfs
pinkish
where igneous rocks have Kfs
felsic
what cleavage does plagioclase have
2 perfect at 90˚
what twinning does plagioclase have
multiple twinning
what colour is plagioclase usually found
white
what igneous rocks have plagioclase
basically all of them
what colour and shape is ampibole
dark coloured with long bladed crystals
what cleavage does amphibole have
120/60˚
what igneous rocks have amphibole
felsic to mafic
what cleavage does pyroxene have
two perfect 90˚
what colour is pyroxene
dark coloured green
what shape is pyroxene
stubby prismatic boxy
what colour is olivine
lighter green
what cleavage or fracture does olivine have
conchoidal fracture
what shape does olivine have
tabular shaped
what igneous rocks have olivine
mafic to ultramafic rocks such as basalt, peridotite.
what minerals are found in granite
pink = feldspar
white = plagioclase
translucent = quartz
black = muscovite
where is granite found
continental crust, convergent boundaries or tectonic activity that makes mountains
what texture does granite have
phaneritic
is granite plutonic or volcanic
plutonic (coarse grained - cooled slowly)
what minerals are found in rhyolite
quartz, plagioclase, Kfs and micas
what is the silica content of granite and rhyolite
> 60%
is rhyolite plutonic or volcanic
volcanic (fine grained - cools rapidly)
what minerals are present in diorite
white tabular = plagioclase
black elongate = amphibole
glassy = quartz
what is the texture and grain size of diorite
phaneritic and coarse
what minerals are present in andesite
amphiboles, plagioclase, quartz and micas
what is the texture and colour of andesite
darker coloured aphanitic
what minerals are present in gabbro
plagioclase, pyroxenes, amphiboles
what texture and grain size is gabbro
coarse grain phaneritic
what minerals are present in basalt
olivine, plagioclase phenocrysts, amphiboles, pyroxenes
what texture and colour is basalt
dark coloured, fine grained aphanitic or porphyritic if it has phenocrysts
what minerals are in peridotite
olivine, pyroxene
what texture is peridotite
phaneritic, coarse grained
what are distinguishing features of garnet
conchoidal fracture, bright red and found in many high grade metamorphic rocks
what are features of andalusite
organgish, elongated prisms, in low grade metamorphism
what are features of kyanite
associated with regional metamorphism, bladed prisms, blue colour
what are features of sillimanite
colourless to white, bladed prisms, associated with regional metamorphism
what are the two calcareous metamorphic minerals
epidote and wollanstonite
what are features of epidote
green and rocks that are hydrothermally metamorphosed
wollastonite features:
two perfect cleavages and associated with contact metamorphism. formation by quartz and calcite
calcium silicate hornfels
what are the 3 aluminosilicates in order of least to greatest
andalusite, kyanite and sillimanite
what are the phylosilicate metamorphic minerals
serpentine and talc
distinguishing features of chlorite
greenish colour, associated with low grade metamorphism
what are the minerals of slate
muscovite
Kfs
quartz
chlorite
what are the 4 foliated rocks
slate, phyllite, schist and gneiss
what are the features of slate
slaty cleavage, very fine grained, minerals so fine unable to see
what are the features of phyllite
garnet bearing, muscovite that has been foliated, sheen on slaty cleavage, fine grained, low grade regional metamorphism
what are the features of schist
fine to medium grained, schistosity, with micas, wavy shiny texture,
what is the protolith to phyllite
siltstone, mudstone or shale
what minerals are present in schist
micas, chlorites, quartz and garnets
what does shale turn into if its subject to low grade contact metamorphism
hornfels
what are the features of gneiss
garnet, sillimanites, pyroxene, gneiss banding
protoliths to gneiss
shale or granite under regional high grade metamorphism
what are the features of sillimanite gneiss
dominantly sillimanite, serpentine, rich in aluminium with bladed crystal banding
kyanite schist features
blue white elongated crystals: kyanite
black platy with perfect cleavage: biotite
regional high grade metamorphism
features of granitic gneiss
gneissic banding with quartz, micas, Kfs and plagioclase
what are the features of serpentine group
fibrous, green coloured
sillimanite gneiss minerals:
sillimanite, quartz, biotite, feldspars and garnet
features of andalusite hornfels
andalusite, biotite, coarse grained. protolith is mudstone
can molybdenite be found in placer deposits with gold and or cassiterite
no because moly is relatively easy to weather and erode, lower specific gravity compared to the other two.
features of galena
cubic, heavy, perfect 3 cleavages and bright metallic lustre
features of pyrite
brass yellow colour, fools gold
Chalcopyrite features
multi coloured usually brass yellow colour, brittle fracture
sphalerite features
range of colours but usually transparent, fractures are uneven
features of molybdenite
bluish - silver platy mineral habit
