Feldspathoids Flashcards
1
Q
Feldspathoids
A
- structurally similar to Feldspars except more open
- 4 and 6 member rings
- lower specific gravity than Feldspars (2.3)
- cavities are occupied by Na or K anions
2
Q
The chemical reaction of a Feldspathoid creating a Feldspar
A
NaAlSiO4 + 2SiO2 = NaAlSi3O8
Nephaline) (Qtz) (Albite
3
Q
Leucite
A
KAlSi2O6
- occurs in volcanic rocks
- similar to microcline
4
Q
Nephaline
A
NaAlSiO4
- occurs in volcanic rocks
- if present, Quartz is not
- dull lustre
5
Q
3 minerals in sodalite group? (all isotropic)
A
- sodalite
- Nosean
- Hauyne
6
Q
How many Zeolites are there?
A
- 40 naturally occuring
- 600+ synthetic ones
7
Q
What is the largest single group of silicate minerals?
A
- zeolites
8
Q
Zeolites are commonly an alteration product of what rocks?
A
basaltic and andestic volcanic rocks
9
Q
Zeolite composition
A
- hydrated framework silicates
- Si/Al ratio varies from 1-6
- cation = Na+, K+, Ca2+
10
Q
3 Zeolite examples
A
Natrolite
Laumonite
Analcite
11
Q
common uses of Zeolites
A
disiccants = solids that absorb water (like silica packs)
water softeners = Na-rich zeolites remove Ca from water and replace
water purification
