Grass-green, olive-green, yellow-green, siskin-green, blackish brown, nearly black
Crystal habit
Encrustations, aggregates of plume-like forms and radial crystals[2]
Cleavage
None observed
Fracture
Irregular/uneven, sub-conchoidal
Tenacity
Brittle
Mohs scale hardness
3 – 3+1⁄2
Lustre
Greasy
Streak
Yellowish green
Diaphaneity
Transparent, opaque
Specific gravity
5.9
Optical properties
Usually biaxial (−) rarely biaxial (+)
Refractive index
nα = 2.170(2) nβ = 2.260(2) nγ = 2.320(2)
Birefringence
δ = 0.150
Pleochroism
Visible X=Y= canary yellow to greenish yellow, Z= brownish yellow
2V angle
Measured: 73° , calculated: 46°
Dispersion
Strong r > v rarely r < v
Solubility
Readily soluble in acids[3]
Common impurities
Zinc
References
[2][3][4][5][6]
Mottramite is an orthorhombic anhydrous vanadate hydroxide mineral, PbCu(VO4)(OH), at the copper end of the descloizite subgroup. It was formerly called cuprodescloizite or psittacinite (this mineral characterized in 1868 by Frederick Augustus Genth). Duhamelite is a calcium- and bismuth-bearing variety of mottramite, typically with acicular habit.[3]
Mottramite is a member of the adelite-descloizite group.[3]
Mottramite, which is a copper rich member, forms a series with descloizite, which is a zinc rich member.[3][5] These two minerals usually contain significant percentages of both copper and zinc and are seldom pure. Mottramite also forms a series with duftite.[3]
It was discovered in 1876[3] and named for the locality, Mottram St Andrew, Cheshire, England, where ore was stockpiled, although it was probably mined from Pim Hill Mine, Shrewsbury, Shropshire, England.[3][5][7]
^Gaines et al (1997) Dana’s New Mineralogy, Eighth Edition. Wiley
^ abcMottramite in the Handbook of Mineralogy
^Mineralienatlas
^Kingsbury and Hartley (1956). New occurrences of vanadium minerals (mottramite, descloizite, (discredited) and vanadinite) in the Caldbeck area of Cumberland. Mineralogical Magazine 31:289
bismuth-bearing variety of mottramite, typically with acicular habit. Mottramite is a member of the adelite-descloizite group. Mottramite, which is a copper rich...
after mimetite have also found. It occurs in association with olivenite, mottramite, azurite, malachite, wulfenite and calcite in the Tsumeb, Namibia deposit...
vanadinite, wulfenite Plumose Fine, feather-like scales aurichalcite, okenite, mottramite Radial/Radiating/Divergent Radiating outward from a central point without...
decline, potentially reducing natural calcite production. Calcite with mottramite Trilobite eyes employed calcite Calcite crystals inside a test of the...
of lead ores in association with pyromorphite, vanadinite, wulfenite, mottramite, mimetite and cerussite. The Otavi ("O-tarvi") Mountainland of northern...
silicates. Associated minerals include mimetite, pyromorphite, descloizite, mottramite, wulfenite, cerussite, anglesite, calcite, barite, and various iron oxide...
cerussite, hemimorphite, smithsonite, vanadinite, anglesite, pyrite, mottramite, willemite, and wulfenite. Good specimens have been reported from Gila...
other localities, francevillite is associated with duttonite, vanuralite, mottramite, carnotite, dewindtite, torbernite, uranopilite, johannite and kasolite...