Descloizite has been found at the Brown Monster mine, associated with
mottramite. It is brown in color and tends to form larger crystals (to 0.25 mm) than the
mottramite, which is typically more micro-botryoidal.
In 1865 Roscoe was inspired to begin investigating vanadium when he visited the copper mines at Mottram (the type locality for the vanadium mineral
mottramite, described by Domeyko in 1848), near Alderley Edge in Cheshire.
Rarely, small pyromorphite crystals are seen embedded in crusts of blue botryoidal hemimorphite and very rarely pyromorphite is found associated with small rounded
mottramite crystals.
White to colorless, translucent to transparent, flattened rhombohedral crystals of calcite to 3 cm form floater groups heavily coated and/or included by bright yellow-green, fernlike growths of
mottramite crystals.
These include arseniosiderite, bromargyrite, cabalzarite, chalcophyllite, clinoclase, clinotyrolite, cobaltkoritnigite, cornubite, fornacite, geminite, litharge,
mottramite, nickellotharmeyerite, novacekite, parnauite, powellite, uvarovite, walentaite, wulfenite, yukonite and zalesiite.
Other associated minerals are: cerussite, bindheimite, vauquelinite,
mottramite and pyromorphite.
Crystals of both types reach 2.5 cm on edge, and they perch at high angles on drusy coatings of black
mottramite microcrystals and tiny quartz crystals over rock.
Associated minerals are: manganite, quartz, barite, ankerite,
mottramite barian brackebuschite and cuprian-cobaltoan pyrobelonite.
A third specimen is a sample of
mottramite, together with an X-ray pattern identifying the mineral as such.
Associated minerals are azurite, quartz, plancheite, cerussite and
mottramite. Good dioptase specimens have also been reported from copper prospects at M'Foati.
Conversely, a number of species occurring at the Blanchard mine (antlerite, cinnabar, hydrozincite, sulfur,
mottramite, otavite, and cuprite) have not been found at the Mex-Tex mine.
The mineralogy and geochemistry of this gossan have been described by Nickel (1982), who noted the occurrence of a number of secondary ore minerals including malachite, azurite, chrysocolla, pseudomalachite, cerussite, alunite, jarosite, plumbojarosite, osarizawaite, plumbogummite, duftite, mimetite, fornacite, wulfenite,
mottramite, iodargyrite, native silver and a silver-mercury amalgam.