Roscoelite

Roscoelite
Roscoelite and gold
General
CategoryPhyllosilicate
Formula
(repeating unit)
K(V3+,Al,Mg)2AlSi3O10(OH)2
IMA symbolRcl[1]
Strunz classification9.EC.15
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupC2/m
Identification
Formula mass426.53 g/mol
Colourolive-green to green-brown
Crystal habitscales, fans, druses, rosettes, fibrous or felted aggregate.
CleavagePerfect plane {0,0,1}
Fractureplaty
Mohs scale hardness1
Lustrepearly
Diaphaneitysemi-transparent to translucent
Specific gravity2.92 - 2.96
Optical propertiesBiaxial (-)
Refractive indexnα=1.60 nβ=1.66 nγ=1.67
Birefringenceδ =
Pleochroismolive green to green-brown
Fusibilityloses water

Roscoelite is a green mineral from the mica group that contains vanadium.

The chemical formula is K(V3+, Al, Mg)2AlSi3O10(OH)2.[2] Crystals of roscoelite take on the monoclinic form, and are from the 2/m point group. The appearance is semi transparent to translucent coloured olive brown to green brown. The lustre is pearly. The mineral shows pleochroism with X showing green-brown, and Y and Z axes showing olive-green colour. The mineral was named after Henry Enfield Roscoe who first produced vanadium metal.

  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ Roscoelite information[full citation needed]