General Information:
Chemical Formula:
(Na,K)AlSi3O8
Composition:
(Molecular Weight = 266.25 gm)
Potassium 3.67 % K
Sodium 6.48 % Na
Aluminum 10.13 % Al
Silicon 31.65 % Si
Oxygen 48.07 % O
Empirical Formula:
Na0.75K0.25AlSi3O8
Environment:
Andesitic lavas.
Locality:
Pantelleria. Southwest of Sicily.
Physical Properties:
Cleavage:
[001] Perfect, [010] Good
Color:
colorless, green, gray, gray pink, or yellow.
Density:
2.57 - 2.6, Average = 2.58
Diaphaniety:
Transparent
Habits:
Disseminated - Occurs in small, distinct particles dispersed in matrix., Granular - Generally occurs as anhedral to subhedral crystals in matrix.,
Hardness:
6 - Orthoclase
Luster:
Vitreous (Glassy)
Streak:
white
More details...