Chapter 1- minerals Flashcards
Mineral Definition
Naturally occurring chemical substance with a definite composition and crystalline structure
Rock Definition
an aggregate or mixture of one or more minerals
Sublimation Definition
transition of a substance from solid to gas without passing through the liquid phase
Deposition/De-sublimation
transition of a substance from gas to solid without passing through the liquid phase
Lustre Definition
surface of a mineral ad its appearance as it interacts with lights
Crystal
a solid with plane faces, formed when atoms are arranged in a structurally ordered pattern
Glass Definition
an amorphous solid with no crystalline structure
Grain Boundary
line of contact between mineral crystals in a rock
Most abundant elements in the Earth’s crust (3)
Oxygen (46.6) Silicon (27.7) Aluminium (8.1)
Physical characteristic to identify minerals (8)
Colour, streak, lustre, shape/habit, cleavage/fracture, hardness, density, reaction with acid
Reference minerals for the hardness scale (1-10)
Talc, gypsum, calcite, fluorite, apatite, feldspar, quartz, topaz, corundum, diamond
Mineral: irregular shape, white/grey colour, hardness 7, density 2.7
quartz
Mineral: rectangular shape, pink/white/grey, hardness 6, two cleavage, density 2.6
feldspar
Mineral: sheets, white/grey or black, hardness 2.5-3, one cleavage, density 2.8
mica
Mineral:square shape or eight-sided in cross section, dark green to black, hardness 5.5-6.5, two cleavage at 93, density 3.2-3.6
augite/pyroxene
Mineral: diamond shape in cross section, green-black, hardness 5-6, two cleavage at 60, density 3-3.5
hornblende
Mineral: rounded shape, yellow green, hardness 6.5-7, poor cleavage, density 3.2-4.4
olivine
irregular shape, white/grey/clear, hardness 3, three cleavage, density 2.7, reacts with acid
calcite
Mineral: rounded shape or six sided in cross section, deep red-brown, hardness 6-7.5, no cleavage, density 4
garnet
Mineral: flat blades, blue/white/grey, hardness 5.5-7, two cleavage, density 3.5-3.7
kyanite
Cations
atoms with a net position after loosing 1 or more electrons
anions
atoms with a net negative charge after gaining 1 or more elctrons
Covalent bond
formed by two atoms sharing a pair of electrons
tetrahedron
a solid formed of four triangular plane faces
bridging oxygen
an oxygen atom shared by two SiO2 tetrahedra
polymers
repeating chains of smaller molecules
minerals with a single tetrehedra structure
Olivine
minerals with chain tetrehedra
Pyroxenes
minerals with double chain tetrahedra structure
amphiboles
minerals with sheet tetrahedra structure
micas and clay minerals
minerals with framework tetrahedra structure
quartz and feldspars
polymerisation
when small molecules join up to make larger ones
Diagenesis
all processes that occur in sediments at low temperatures and pressures at or near the earth’s surface
Metamorphism
changing of rocks in the earth’s crust by heat/pressure. isochemical, solid state change
Igneous rock
rock that has crystallised from magma
Metamorphic Rock
formed by recrystallisation of other rocks in solid state due to temperature and/or pressure
partial melting
occurs when only a portion of rock in the lower crust/upper mantle is melted
recrystallisation
solid state process that changes minerals into new crystalline metamorphic minerals
crystallisation
occurs during cooling of magma/lava so solid mineral crystals form
burial
occurs when sediment is covered by younger layers of sediment
sedimentary rock
rock composed of fragments that have been deposited, compacted, and cemented
clast
fragment of broken rock produced by mechanical weathering and erosion
Magma accumulation
magma collecting within a magma chamber
intrusions
igneous rock formed below the earth’s surface where magma is forced into pre-existing rocks
extrusions
emission of magma onto the earth’s surface where it forms a lava flow
folliation
texture in metamorphic rocks formed by preferred alignment of flat/tabular minerals
deposition
laying down of sediment, occurring when the transportation agent loses energy
weathering
breakdown of rocks in situ
erosion
removal of weathered material, usually by physical action of transported fragments
transport
means by which weathered material is moved from one place to another by wind, water, ice or gravity
uplift
return of buried rocks to the earth’s surface by tectonic action
