Luis Burillo brought to his InnSuites room in Tucson, besides the Peruvian rhodonites and Romanian
berthierites already described, a selection of small-but-choice liddicoatite specimens of two different styles, found of late at two different places in Madagascar.
The mineral forms rare microscopic fibrous intergrowths with jamesonite and berthierite in 3mm-thick veins.
Gudmundite occurs commonly as isolated, anhedral, isometric grains to 2 mm and in aggregates to 5 mm, mainly in stibnite, berthierite, quartz and carbonates.
It forms typical acicular intergrowths ([less than or equal to]1 mm) with berthierite and boulangerite (?) in small veins (Cambel, 1959).
Berthierite was identified by X-ray analysis in a sample collected by the British Columbia Geological Survey.
Berthierite occurs both as rich black masses and more sparingly as iridescent, prismatic, microcrystals in the gudmundite-albite-dolomite assemblage.
Berthierite is also present on the specimen, and the schafarzikite may have been formed by alteration of that mineral.
In the gudmundite-albite-dolomite assemblage, quartz, albite, pyrrhotite and dolomite appear to be the earliest minerals to have formed, followed by berthierite, gudmundite, stibnite and adularia (?), then by minor native antimony and chlorite.