4 minerals Flashcards
atoms, isotopes and ions
Protons, neutrons, electrons
Change the number of protons
Change the element (He = 2 protons; Li = 3 protons)
Change the number of neutrons
Change the isotope (4He = 2 neutrons; 6He = 4 neutrons)
Change the number of electrons?
Creates positive and negative ions
Losing an electron = positively charged ion
Gaining an electron = negatively charged ion
Attraction between + and – binds ions together
bonding
Ionic: Giving/taking electrons
Covalent: Sharing electrons
states of matter caused by what?
Pressure and temperature
Determine the STATE in which matter exists
mineral requirements
Naturally occurring
Inorganic (not made by biological processes)
Solid
Specific internal structure
Specific chemical composition
With defined, limited variation
Specific physical properties
Mineral reqs (mr): solid
Minerals must have a crystalline structure
Solids lacking an internal atomic order are called glasses
mr specific internal structure
Controls the physical properties of minerals
Geometry of the atomic packing
Type of bonding
physical properties of a mineral:
Crystal form: Arrangement of atoms in the mineral dictate the crystal form
Cleavage: Reflection of planes of weakness within the crystal structure. Concoidal fracture
When the mineral doesn’t have a plane of weakness
Hardness
Density
Color
Luster
Streak
Magnetism
Cleavage
Reflection of planes of weakness within the crystal structure. Concoidal fracture
When the mineral doesn’t have a plane of weakness
hardness
resistance to scratching: Reflects the strength of the atomic bonds in the crystal structure
Mohs Hardness Scale
the difference between each of these is not equal but the order is correct
1Talc
2Gypsum
3Calcite
4Fluorite
5Apatite
6Orthoclase
7Quartz
8Topaz
9Corundum
10Diamond
Density
Depends upon the KINDS of elements in the mineral and how CLOSELY packed they are
Color
Not so helpful, sadly
Luster
Appearance of reflected light
Controlled by bonding between atoms
Streak
Color of mineral in powdered form (not always the same color as mineral)
Magnetism
Only a very few minerals are strongly magnetic (magnetite)
Crystallization and destruction
Crystallization
-Addition of ions to the crystal face
-Unrestricted
Crystal form
-Restricted
Takes on the shape of the space
Internal structure is the same
Destruction
Melting
Dissolving
Recrystallizing
Crystallization
Solidification
From molten rock
Precipitation
Out of solution
Gases or liquids
Biomineralization
Not truly minerals (organic!)
Production of “minerals” by organisms
Diffusion
Atoms migrating through the crystals and creating new minerals
Major rock forming minerals: silica
Silicates
95% of the Earth’s crust
Based on the arrangement of the silica tetrahedron=silica center with four oxygens attached in pyramid shape around it
common crustal silicates in order of increased complexity and decreased temp.
Common crustal silicates:
Olivine
Pyroxene
Amphibole
Micas
Two types: muscovite and biotite
Feldspars
Two types: potassium feldspar and plagioclase feldspar
Quartz
Silicate groups
felsic and masic
felsic
Rich in silica and aluminum
Generally light colored
Low density
Crystallize in low temperature
More common in the continental crust
Feldspar
Quartz
Muscovite Mica
mafic
Rich in iron (Fe) and magnesium (Mg)
Generally dark colored
Higher density
Crystallize in high temperature
More common in the oceanic crust
Olivine
Pyroxene
Amphibole
Biotite Mica
f: feldspar
Feldspar
Good cleavage, hardness of 6
Most abundant mineral in Earth’s crust
Potassium feldspar
Plagioclase feldspar
Chemically breaks down relatively easily
f: quartz
Conchoidal fracture, hardness of 7
Very stable
Doesn’t chemically break down easily
F: muscovite mica
Perfect one-directional cleavage
Break into little sheets
M: olivine
Olivine
High density
Glassy luster
Usually found in basalt
M: pyroxene
Pyroxene
Two directions of same degree cleavage
M: Amphibole
Two directions of different degree cleavage
M: biotite mica
Perfect one-directional cleavage
Break into little sheets
olivine is always what
green
major rock forming minerals
Silicates
95% of the Earth’s crust
Based on the silica tetrahedron
Arrangement of silica tetrahedron
Non-silicates
Usually carbonates or sulfates
Often economically important
non silicate minerals
Calcite (CaCO3)
Rhombohedral cleavage
Hardness of 3, fizzes in HCl acid
Precipitates out of the oceans
Halite (NaCl)
Rock salt!
Cubic cleavage, tastes salty
Formed by evaporation of seawater or salt lakes
Gypsum (CaSO4 + water)
Hardness of 2, can be clear
Formed by evaporation of saline lakes
Oxides
Ore minerals!
Some are magnetic
