“This SEM micrograph (BSE mode) of pale yellowish crusts reveals spheroidal to rosette-like aggregates which, according to EDS-analyses, grade from Fe-rich hidalgoite to Al-rich beudantite. The tiny white, acute crystal on the left is mimetite.
The specimen, which was found by Fritz Schreiber in 2010, also contained tiny dark brownish, strongly rounded crystal of As-rich plumbojarosite (http://www.mindat.org/photo-728284.html).”
Uwe Kolitsch - 22nd January 2016