General Information:
Chemical Formula:
Ca2Al4Si4O16·9(H2O)
Composition:
(Molecular Weight = 718.55 gm)
Calcium 11.16 % Ca
Aluminum 15.02 % Al
Silicon 15.63 % Si
Hydrogen 2.52 % H
Oxygen 55.67 % O
Empirical Formula:
Ca2Al4Si4O16·9(H2O)
Environment:
Alteration product of plagioclase.
IMA Status:
Approved IMA
Locality:
Albani Mountains, south of Rome, Italy.
Name Origin:
Named after the Italian mineralogist, C. G. Gismondi (1762-1824).
Physical Properties:
Cleavage:
[101] Imperfect
Color:
blue white, colorless, gray, white, or red.
Density:
2.26
Diaphaniety:
Transparent to translucent
Habits:
Pseudo Tetragonal - Crystals show a tetragonal shape., Globular - Spherical, or nearly so, rounded forms (e.g. wavellite).,
Hardness:
4-5 - Fluorite-Apatite
Luster:
Vitreous (Glassy)
Streak:
white
More details...