General Information:
Chemical Formula:
NaMg2Fe+++5(SO4)7(OH)6·33(H2O)
Composition:
(Molecular Weight = 1,719.83 gm)
Sodium 1.34 % Na
Magnesium 2.83 % Mg
Iron 16.24 % Fe
Hydrogen 4.22 % H
Sulfur 13.05 % S
Oxygen 62.33 % O
Empirical Formula:
NaMg2Fe3+5(SO4)7(OH)6·33(H2O)
Environment:
Formed as a weathering product of pyritic shales. Found with other acid (low pH) sulfates.
Locality:
Valachov Hill, near Skrivany, Bohemia, Czech Republic.
Name Origin:
Named after the Czech mineralogist, Frantisek Slavik (1876-1957).
Physical Properties:
Color:
yellowish green.
Density:
1.9 - 2.1, Average = 2
Diaphaniety:
Transparent
Habits:
Crystalline - Fine - Occurs as well-formed fine sized crystals., Encrustations - Forms crust-like aggregates on matrix., Granular - Generally occurs as anhedral to subhedral crystals in matrix.
Hardness:
3.5 - Copper Penny
Luster:
Vitreous (Glassy)
Streak:
pale yellowish green
More details...