Anhydrous vanadate containing hydroxyl
Duhamelite is a calcium and bismuth bearing variety of mottramite
Specific gravity: 5.9
Hardness: 3 to 3½
Colour: Grass-green, olive-green, yellow-green, siskin-green, blackish brown, nearly black
Solubility: Readily soluble in acids
Mottramite is a secondary mineral associated with
descloizite in oxidised zones,
especially in sandstone.
At Tsumeb, Namibia, mottramite pseudomorphs after cerussite, after calcite, after wulfenite on lead-rich calcite and after copper with calcite have been found (KL p200-203).
At Mottram St Andrew, Cheshire, England, UK, mottramite occurs as an encrustation on sandstone, associated with duftite, later mimetite and pyromorphite and plumbogummite (RES pps 58-60).
At Arm O'Grain, Caldbeck, Cumbria, England, UK, mottramite has been found on a quartz matrix (AESS).
At Peldar Tor quarry, Spring Hill, Whitwick, Leicestershire, England, UK, mottramite crystals have been found on a calcite, dolomite and quartz matrix (RES p201).
At Pim Hill mine, Harmer Hill, Shropshire, England, UK, mottramite occurs on sandstone (RES p292).
At Judkins quarry, Nuneaton, Warwickshire, England, UK, mottramite has been found with baryte, coating calcite (RES p324).
At the Total Wreck mine, Cochise county, Arizona, USA, pseudomorphs of mottramite after wulfenite have been found (R&M 94.2.169).
At the Kabwe mine, Central Province, Zambia, mottramite has been reported in dolomite, with inclusions of rosasite (R&M 94.2.130).
Common impurities: Zn
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