General Information:
Chemical Formula:
CaAl2Si6O16·5(H2O)
Composition:
(Molecular Weight = 608.62 gm)
Calcium 6.59 % Ca
Aluminum 8.87 % Al
Silicon 27.69 % Si
Hydrogen 1.66 % H
Oxygen 55.20 % O
Empirical Formula:
CaAl2Si6O16·5(H2O)
Environment:
Alteration product in basalts.
IMA Status:
Approved IMA 1972
Locality:
Berufjord, Iceland.
Name Origin:
From the Greek epi - "near" and the mineral Stilbite.
Physical Properties:
Cleavage:
[010] Perfect
Color:
white, yellowish white, reddish white, or brownish white.
Density:
2.2 - 2.3, Average = 2.25
Diaphaniety:
Transparent to translucent
Habits:
Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline)., Spherical - Spherical, rounded aggregates., Twinning Common - Crystals are usually twinned.
Hardness:
4-5 - Fluorite-Apatite
Luminescence:
None.
Luster:
Vitreous (Glassy)
Streak:
white
More details...