Characteristics seen in cross polarized light Flashcards
1
Q
What is optical indicatrix?
Aksialitet
A
Variations in R.I.
2
Q
Are most minerals anisotropic og isotropic?
Optisk modus
A
Anisotropic - The atom order is different in different direction.
=> R.I. varieres with direction
ex. sheet silicates,
3
Q
Examples of isotropic minerals
Optisk modus
A
Atomic arrangement is the same along all crystalographic axes
Amorphous mineroloids => glass, obsidian
Cubis crystal systems => Pyrite, halite, Galena
4
Q
Which mierals grains are used to determine birefringence?
A
Mineral grains with highest interference color
5
Q
Which mineral grains are used to determine the optic indicatrix of the mineral?
Uniaxial vs. biaxial
A
Grains with relative low birefringence
6
Q
A
