Diadochite is a
phospho-sulfate
The sulfate or sulphate ion is a polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many ...
mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2 ...
. It is a secondary mineral formed by the weathering and hydration of other minerals. Its formula is Fe
2(PO
4)(SO
4)OH·5H
2O. Well crystallized forms are referred to as ''destinezite'', which has been given official recognition by the
International Mineralogical Association with diadochite being the poorly formed to amorphous variety.
It has a greenish yellow to brown colour and forms nodules or crusts. Its appearance has been compared to
cauliflower.
Identified originally in
Belgium
Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to th ...
in 1831, it has been found in many places throughout the world.
It occurs as a secondary mineral in mineral
gossan
Gossan (eiserner hut or eisenhut) is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein. In the ''classic'' gossan or iron cap all that remains is iron oxides and quartz, often ...
s,
coal
Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen.
Coal is formed when ...
deposits, phosphate rich
pegmatites and
cave
A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea ...
guano deposits.
[http://rruff.geo.arizona.edu/doclib/hom/diadochite.pdf Handbook of Mineralogy]
References
Webmineral
Iron(III) minerals
Phosphate minerals
Sulfate minerals
{{phosphate-mineral-stub