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Formula: Mn2+9Fe3+3(PO4)8(OH)3.9H2O
Hydrated phosphate, phosphoferrite group,
manganese-bearing mineral
Crystal System: Orthorhombic
Specific gravity: 3.026 measured, 3.210 calculated
Hardness: 3 to 3½
Colour: Red-brown; yellowish brown in transmitted light
Environments
Landesite occurs as an alteration product of reddingite
(Mindat).
At the type locality, the Berry-Havey Quarry, Poland, Androscoggin County, Maine, USA, landesite occurs replacing
reddingite in a complex
granite pegmatite.
Associated minerals include reddingite,
lithiophilite, rhodochrosite,
eosphorite, fairfieldite and
apatite
(HOM).
The feldspar was replaced first by
amblygonite, which may have filled the entire pocket. Then
manganese-rich solutions replaced the greater part of the
amblygonite with rhodochrosite
which in turn was cut by veinlets of quartz. Later
manganese solutions attacked the
rhodochrosite leaving central cavities in the pockets into which were
introduced the manganese phosphates,
eosphorite, reddingite,
dickinsonite and fairfieldite,
followed by apatite. Last of all
supergene alteration changed the
reddingite to landesite, and a general
manganese staining was the final step
(AM 15.375-387).
Landesite from the Berry-Havey Quarry - Image
At the Emmons pegmatite, Greenwood, Oxford county, Maine, USA, landesite has been found as an alteration crust on
reddingite. The Emmons
pegmatite is an example of a highly evolved
boron - lithium -
cesium - tantalum-
enriched pegmatite
(R&M 94.6.509).
Landesite from the Emmons Quarry - Image
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