Minerals Flashcards
What’s the difference between Silicon, Silica and Silicate?
Silicon - The element
Silica - SiO2
Silicate - Any mineral that contains silica
What are the 5 silicate structures?
- Single Tetrahedra (SOLO)
- Chain (CHAP)
- Double Chain (DAM)
- Sheet (SHIMMER)
- Framework (FRACTURE - QUICK!)
What minerals have a single tetrahedra?
Olivine (SOLO - O = OLIVINE)
What minerals have a single chain?
Pyroxene aka Augite (CHAP - A = AUGITE)
What minerals have a double chain?
Amphibole aka Hornblende (DAM - A = AMPHIBOLE)
What minerals have a sheet structure?
Micas (SHIMMER - M = MICAS)
What minerals have a framework structure?
Quarts, Feldspars (FRACTURES - QUICK! F = FELDSPARS, Q = QUARTZ)
What is the angle between faces on Quartz?
60 degrees
What is the grain boundary?
The line of contact between minerals/crystals in a rock
What are the eight characteristics of minerals used to identify them?
-Colour
-Streak (The colour of the line that is left behind when scratched)
-Lustre (How shiny it is)
-Shape
-Cleavage (A division / split in a mineral/rock)
-Hardness (MOHS HARDNESS SCALE)
-Density (= MASS/VOLUME)
-Reactions with acids (If a rock fizzes with certain acids etc)
What is hardness, colour, lustre, streak, density and cleavage of quartz?
Hardness = 7
Colour = White/Grey/sometimes pink
Lustre = Glassy
Streak = White
Density = 2.7
Cleavage = None
What is hardness, colour, lustre, streak, density and cleavage of calcite?
Hardness = 3
Colour = White/Colourless
Lustre = Glassy
Streak = White
Density = 2.7
Cleavage = At least 3 rhombus cleavages
What is hardness, colour, lustre, streak, density and cleavage of Muscovite + Biotite Micas?
Hardness = 2.5
Colour = Muscovite = Colourless/Silvery, Biotite = Black/Dark brown
Lustre = Glassy
Streak = White
Density = 3
Cleavage = One perfect cleavage so can split easily.
What is hardness, colour, lustre, streak, density and cleavage of hornblende?
Hardness = 5.5
Colour = Dark green/black
Lustre = Glassy
Streak = Light grey
Density = 3.2
Cleavage = Two cleavages at 60 degrees
What is hardness, colour, lustre, streak, density and cleavage of augite?
Hardness = 5.5
Colour = Dark green/black
Lustre = Glassy
Streak = Light grey
Density = 3.4
Cleavage = Two cleavages at 90 degrees
What is hardness, colour, lustre, streak, density and cleavage of K feldspar and Plagioclase feldspar?
Hardness = 6
Colour = White/pink
Lustre = Glassy
Streak = White
Density = 2.6-2.7
Cleavage = Two cleavages that intersect at 90 degrees
What is hardness, colour, lustre, streak, density and cleavage of Olivine?
Hardness = 6.5
Colour = Black/Green
Lustre = Glassy
Streak = White/Pale grey
Density = 3.8
Cleavage = No cleavage
Define Euhedral, Subhedral, Anhedral
- Perfectly formed crystal
- Sub-formed crystal
- Poorly formed crystal/Without shape.
What are the three crystal size groups?
- Fine = < 1 mm
- Medium = 1-5 mm
- Coarse = > 5mm
Define equicrystalline, inequicrystalline, phenocrysts and groundmass
- Crystals are same sizes in a rock
- Crystals are different sizes in a rock
- Large, Euhedral crystals
- Finer sub/anhedral
(3 and 4 are both examples of porphyritic texture)
Define crystallisation
Occurs during the cooling of lava/magma so that solid minerals form
Define recrystallisation
Is the solid state process that changes minerals into new crystalline metamorphic minerals
Define clasts
A fragment of broken rock produced by mechanical weathering and erosion
What is the standard size slice of a rock?
0.03mm
What are geological microscopes called?
Petrological microscopes
What does PPL and XPL stand for?
PPL = plane polarised light - viewed through one polarising filter
XPL = Cross polarised light - viewed through two polarising filters
What is the order of the abundance of elements in the Earths crust?
- Oxygen (OX)
- Silicon (SI)
- Aluminium (AL)
- Iron (F)
- Calcium (AC)
- Sodium (NA)
- Potassium (K)
- Magnesium (MAG)
OXSIALFACNAKMAG
What is the order of the abundance of elements in the Earths mantle?
- Oxygen (OX)
- Silicon (SI)
3.Magnesium (MAG) - Iron (F)
- Aluminium (A)
- Calcium (C)
- Sodium (NA)
- Potassium (K)
OXSIMAGFACNACK
What is the order of the abundance of elements in the Earths mantle?
- Iron (FE)
- Oxygen (O)
- Nickel (NI)
FEONI
How can calcite be distinguished from quartz?
You can use an acid test using DIULUTE HYDROCHLORIC ACID, or test the hardness scale.
What are the 4 salts?
Calcite
Gypsum
Halite
Potassium
What is the formula for NATIVE COPPER?
Cu
What is the formula for NATIVE SULPHUR?
S
What is the formula for calcite?
CaCO3
What is the formula for quartz?
SiO2
What is the formula for galena?
PbS
What is the formula for pyrite?
FeS2
What is glass?
A solid with no crystalline structure
What is a mineral?
A naturally occurring chemical substance having a definite composition and crystalline structure.
What is a rock?
An aggregate mixture of minerals.
What is a crystal?
A solid with plane faced formed when atoms are arranged in an ordered pattern
