Class : Oxides and hydroxides
    Subclass : Oxides
    Crystal system : Cubic
    Chemistry : Sb₂O₃
    Rarity : Rare

Senarmontite is an uncommon antimony oxide resulting from alteration of the stibnite. It is found in the superficial oxidation zones of antimony deposits associated with other oxidized antimony minerals (cervantite, stibiconite, valentinite, etc...). It owes its name to Henri Hureau de Senarmont, professor of mineralogy at the Ecole des Mines in Paris, who was the first to study this mineral. Resinous to adamantine luster, colorless to gray depending on its degree of purity, it frequently occurs in translucent octahedral crystals, and in snowy white to white-gray masses. It is a mineral little known to collectors which can constitute an antimony ore.

Main photo : Senarmontite from Djebel Hamimat, Algeria

In France, we find senarmontite in micro-crystals associated with stibnite in many deposits : Montlamard near Moulins (Allier), in various antimony mines in Haute-Loire such as La Bessade, at the La Forge mine near  Issoire (Puy-de-Dôme), at Rivet in Peyrebrune (Tarn), at the La Ramée mine (Vendée), etc...

Senarmontite has no twinned crystals known.

No scam known for this mineral.