Siderophyllite

A variety of Minerals

Siderophyllite specimen - rock identification

What is Siderophyllite?

Siderophyllite is a rare member of the mica group of silicate minerals with formula KFe2Al(Al2Si2)O10(F,OH)2. The mineral occurs in nepheline syenite pegmatites and granite and aplite greisens. It is associated with microcline and astrophyllite at Pikes Peak, Colorado. It is also found in the alkali pegmatites of Mont Saint-Hilaire, Quebec. It was first described in 1880 for an occurrence near Pikes Peak, Colorado. The name derives from the Greek sideros, iron, and phyllon, leaf, in reference to its iron rich composition and perfect basal cleavage.

Siderophyllite Market Value Calculator

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Siderophyllite Localities Map

See where Siderophyllite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.

Map preview
North ZoneCentral RidgeSouth Basin

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Quick Facts

Physical Properties

Color
Dark green, brown, black
Hardness (Mohs)
2.5

Chemical Properties

Chemical Formula
KFe2+2Al(Al2Si2O10)(OH)2
Elements
Al, Fe, H, K, O, Si
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