General Information:
Chemical Formula:
CaMnMg2Fe+++2(PO4)4(OH)2·8(H2O)
Composition:
(Molecular Weight = 813.34 gm)
Calcium 4.93 % Ca
Magnesium 5.98 % Mg
Manganese 6.75 % Mn
Iron 13.73 % Fe
Phosphorus 15.23 % P
Hydrogen 2.23 % H
Oxygen 51.15 % O
Empirical Formula:
CaMn2+Mg2Fe3+2(PO4)4(OH)2·8(H2O)
IMA Status:
Approved IMA
Locality:
Tip Top pegmatite, Custer, South Dakota, USA.
Name Origin:
Named for Richard H. Jahns (1915-1983), mineralogist and pegmatite expert, Stanford University, Palo Alto, California, USA.
Physical Properties:
Cleavage:
[001] Good
Color:
brown, purplish brown, yellow, yellow orange, or greenish yellow.
Density:
2.706 - 2.718, Average = 2.71
Diaphaniety:
Transparent to Translucent
Hardness:
4 - Fluorite
Luster:
Vitreous - Adamantine
Streak:
white
More details...