Slottaite

slottaite

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Formula: SrFe3+3(PO4)(SO4)(OH)6
Phosphate, alunite supergroup, strontium-bearing mineral
Crystal system: Trigonal
Slottaite is a new mineral, approved in 2024 and to date (May 2025) reported only from the type locality. Pending publication.

Localities

The type locality is the Clara Mine, Oberwolfach, Ortenaukreis, Freiburg Region, Baden-Württemberg, Germany. More than 472 unique mineral species have been recorded from the Clara Mine, placing this mine among the most prolific mineral localities on Earth. There is species-defining strontium in 4 of the 17 minerals first discovered at the Clara Mine. Of these, arsenogoyazite is the most widely distributed with 25 reported localities, while benauite and oberwolfachite are each reported from just three localities, and slottaite remains a one locality mineral at the time of writing (May 2025). Indications are that strontium is present at the Clara Mine in unusual geochemical environments scarcely replicated elsewhere (AM 110.826).
Slottaite has been found as a greenish- to brownish- yellow radiating aggregate in association with colourless quartz and dark brown goethite (Mindat photo).
Slottaite from the Clara Mine - Image

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