General Information:
Chemical Formula:NaCa2Al2(As+++++O4)2F4(OH)·2(H2O)
Composition:(Molecular Weight = 563.98 gm)Sodium 4.08 %
NaCalcium 14.21 %
CaAluminum 9.57 %
AlArsenic 26.57 %
AsHydrogen 0.89 %
H Oxygen 31.21 %
O Fluorine 13.47 %
F Empirical Formula: NaCa2Al2(AsO4)2F4(OH)·2(H2O)
Environment:Found as a secondary phase on mineralized rhyolite.
IMA Status:IMA Approved (Dana # Added)
Locality:La Esperanza mine, Zaragosa mining district, near Madero, State of Durango, Mexico.
Name Origin:Named after the discovery locality.
Physical Properties: Cleavage:[100] Perfect
Color:blue green.
Density:3.24
Diaphaniety:Transparent to Translucent
Habits:Botryoidal - "Grape-like" rounded forms (e.g.. malachite)., Spherical - Spherical, rounded aggregates.,
Hardness:4.5 - Between Fluorite and Apatite
Luminescence:Non-fluorescent.
Luster:Vitreous (Glassy)
Streak:white
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