Saturday, October 27, 2012

Oranges? no, Cacoxenite, as seen through a microscope 18x


Formula:
Fe
3+
24
Al (PO
4
)
17
O
6
(OH)
12
· 17H
2
O


Name: From the Greek κακός for "bad" and ξένος for "guest" due to the fact that the phosphorous content of cacoxenite lessens the quality of iron smelted from ore containing it.
System: Hexagonal
Colour: Yellow to brownish ...
Type Locality: Hrbek Mine, Svatá Dobrotivá (St Benigna), Beroun (Beraun), Central Bohemia Region, Bohemia (Böhmen; Boehmen), Czech Republic | This particular one from La Paloma, Spain
Year of Discovery: 1825
Geological Setting: Common accessory mineral in oxidation zone of magnetic and limonite iron ores, novaculites, rarely in iron rich sediments and soils.
Luster: Silky
Diaphaneity (Transparency): Translucent
Colour: Yellow to brownish yellow, reddish orange, golden yellow, deep orange, green; yellow in transmitted light
Hardness (Mohs): 4-Mar
Density   2.2 - 2.6 g/cm3
Crystal System: Hexagonal
Class (H-M): 6/m - Di-pyramidal
Morphology: Crystals crudely hexagonal, acicular [0001], with a hexagonal cross section at times and indistinct pyramidal faces. Commonly in compact, concentric, spherical to radial aggregates. In bundles, randomly fibrous; as coatings or inter-granular cement.