Mineral - Jahnsite-(CaMnMg)
Jahnsite-(CaMnMg)
Chemical Properties
Mineral Class
Phosphates
Toxicity
none
Formula
{Ca}{Mn²⁺}{(Mg,Fe²⁺)₂}{Fe³⁺₂}(PO₄)₄(OH)₂ · 8H₂O
Unit Cell
a=14,94 b=7,14 c=9,93 β=110° Z=2
Physical Properties
Hardness
4
Streak
white
Density
Normal (2-3,5)
Cleavage
Gut nach {001}
Fracture
Tenacity
Brittle
Optical Properties
Color
brownorangeyellow
Birefringence
0,030
Luster
Vitreous,
Adamantine,
Resinous
Transparency
translucent,
transparent
Pleochroism
Geomineralogical Properties
Crystal System
monoclinic
Point Group
Space Group
Habit
prismatic, radial, tabular
Formation
Ein spätes hydrothermales Zersetzungsprodukt von primärem Triphylit-Lithiophilit in Granitpegmatiten
Paragenesis
Twinning
Spiegelung an {001}, wodurch ein pseudo-orthorhombisches Aussehen entsteht
Rarity
Rarely
Synonyms
Jahnsite-(CaMnMg)
Composition
Elements
Mass
P₂O₅
32,2
Al₂O₃
2,1
Fe₂O₃
15,1
MnO
8,0
MgO
9,4
CaO
6,6
H₂O
18,8
South Dakota
Groups and Members
Jahnsit-Gruppe
Jahnsit-Subgruppe