General Information:
Chemical Formula:
(K,Na,Ca)(Al7Si17O48)·22H2O
Composition:
(Molecular Weight = 1,865.00 gm)
Potassium 1.26 % K
Sodium 0.37 % Na
Calcium 0.21 % Ca
Aluminum 10.13 % Al
Silicon 25.60 % Si
Hydrogen 2.38 % H
Oxygen 60.05 % O
Empirical Formula:
K0.6Na0.3Ca0.1Al7Si17O48·22(H2O)
Environment:
Alteration product of basalts.
IMA Status:
Approved IMA 1999, Dana # Added
Locality:
Fara Vicentina, Vicenza, Italy.
Name Origin:
Named after the German mineralogist and chemist, Christian Gottlob Gmelin (1792-1860) of Turbingen, Germany. The K-dominant member of the gmelinite series.
Physical Properties:
Cleavage:
[1010] Good, [0001] Parting
Color:
white, reddish white, pink, greenish white, or flesh red.
Density:
2.03 - 2.17, Average = 2.09
Diaphaniety:
Transparent to translucent
Habits:
Crystalline - Coarse - Occurs as well-formed coarse sized crystals., Druse - Crystal growth in a cavity which results in numerous crystal tipped surfaces.,
Hardness:
4.5 - Between Fluorite and Apatite
Luminescence:
Piezoelectric.
Luster:
Vitreous - Dull
Streak:
white
More details...