General Information:
Chemical Formula:
(Ca,Na2,K2)5Al10Si38O96·25(H2O)
Environment:
Hydrothermal zeolite that generally occures in silica-rich environments in late states of granitic pegmatites and Si-rich basalts.
IMA Status:
Approved IMA (Dana # Added)
Locality:
Filone della Speranza, Monte Capanne, San Piero di Campo, island of Elba, Tuscany, Italy..
Name Origin:
Named after Antonio D'Achiardi (1839-1902), Professor of Mineralogy, Universit di Pisa, Italy, who first described the mineral discovered by his son in a granitic pegmatite.
Physical Properties:
Cleavage:
[100] Perfect, [001] Perfect
Color:
white, pink, or orange red.
Density:
2.14 - 2.21, Average = 2.17
Diaphaniety:
Transparent to translucent
Habits:
Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline)., Twinning Common - Crystals are usually twinned., Pseudo Octohedral - Crystals show an octohedral outline.
Hardness:
4-4.5 - Between Fluorite and Apatite
Luster:
Vitreous - Silky
Streak:
white
More details...