Cacoxenite

(n.)
A hydrous phosphate of iron occurring in yellow radiated tufts. The phosphorus seriously injures it as an iron ore.
  

General Information:
 Chemical Formula:
(Fe+++,Al)25(PO4)17O6(OH)12·75(H2O)
 Composition:
(Molecular Weight = 4,481.51 gm)
Aluminum 3.76 % Al
Iron 23.37 % Fe
Phosphorus 11.75 % P 
Hydrogen 3.64 % H 
Oxygen 57.48 % O 
 Empirical Formula:
Fe2+18.75Al6.25(PO4)17O6(OH)12·75(H2O)
 Name Origin:
From the Greek kakos, meaning "wrong" and xenos, meaning "guest.;"
Physical Properties:
 Cleavage:
None
 Color:
brownish yellow, green, yellow, golden yellow, or red yellow.
 Density:
2.3 - 3.4, Average = 2.84
 Habits:
Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite), Acicular - Occurs as needle-like crystals., Stellate - Occurs as spherical, radial aggregates radiating from a "star" like point.
 Hardness:
3-3.5 - Calcite-Copper Penny
 Luminescence:
None.
 Luster:
Silky
 Streak:
yellow
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