by Justin Kuropas 2 years ago
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Can use the miller indices to make stereographic projections
Kamacite samples have Neumann lines, which is twinning formed by impact shockwaves
These two minerals form Widmastätten patterns when they are together and experience slow cooling
Inclusions in the patterns are Troilite nodules. Black FeS inclusions
These patterns are alternating bands of kamacite and taenite
Plessite - a fine-grained mixture of kamacite and taenite forms last and fills in the gaps
Vapor Phase Growth
Uses chemical vapor deposiition and sublimation. commonly used to make diamonds in a high cost, but high speed process
Solution Growth
Simulate natural conditions for gems that melt incongruently, and it has a low yield for a high cost
Melt Growth
Uses congruent melting, and yields a high volume for a low cost
Filling
Easy to detect, but can make the gem look more smooth
Heat treatment
Changes color of the gem and is irreversible
Every other stone
Sapphire
Ruby
Emerald
Diamond
4 C's
Clarity
I3 - most inclusions
FL - no inclusions (flawless)
Z - Most yellow
D - most clear
Carat
Mass 1 ct = 0.2 g 1 pt = 0.001 ct
Cut
Shape and style of how the gem was cut
Shows the co-evolution of the geosphere and the biosphere
helps to predict the occurrence and location of mineral species
Tetrahedral network - SiO2
Sheet - Si2O5
Double Chain - Si4O11
Single Chain - Si2O6
Tetrahedral Ring - Si6O18
Double tetrahedra - Si2O7
Isolated tetrahedron - SiO4
Low Birefringence - Lack of color like quartz
High Birefringence - Color on edges like calcite
Anisotropic
Biaxial
Trichroic
Uniaxial
Dichroic
Isotropic
Always extinct
Birefringence
Extinction
Zonation
Optical Twinning
Color and Pleochroism
Relief Lines
Refraction Indices
Omission
Interstitial
Substitution
Coupled
Simple
Orthorhombic
Crystal Systems
Isometric
Hexagonal
Trigonal
Tetragonal
Orthrohombic
Monoclinic
Triclinic
Bravais Lattices
Point Groups
Define Crystal Classes. Found by combing 14 unit cells with 4 centering types - 32 possible after redundancies
Non-centrosymmetric
Neither
Polar Enantiomorphic
Enantiomorphic
Polar
Centrosymmetric
inversion center present
Space Groups
Found by combining Point groups and Bravais lattices and screw, glide. Unit cells and all symmetry operations - 230 space groups.
Define a crystalline arrangement and its (finite) frontiers
Found by combining 4 centering types with 7 lattice systems - 14 possible after redundancies
Centering Types
Face-centered
Body-centered
Base-centered
Primitive
Ranked by most Symmetry 1. Isometric 2. Hexagonal 3. Rhombohedral 4. Tetragonal 5. Orthorhombic 6. Monoclinic 7. Triclinic
Polysynthetic
Parallel Association
Cyclic Twinning
Hierarchy of Forms
Euhedral
Subhedral
Anhedral
Dodecahedra
Octahedra
Disphenoids
Tetrahedra
Scalenohedra
Trapezohedra
Dipyramids
(Di)___Pyramids
Prisms
Pinacoids
Pedions
Full Spectrum
Monochromatic
Powder
Crystal
Quasicrystals existence lead to a new definition. It is a crystal if it has an essentially sharp diffraction pattern
Allochromatic
Idiochromatic
Olivine
Mica
Lithium (Spodumene)
Garnet
Quartz
State Gem Emerald
Discovery of Gold
Mineral Research Laboratory