Earth Sciences
Collections

Mariposite

UNB-2017-0194Minerals » Silicates » Phyllosilicates

Description

Three samples of massive/platy Mariposite. The largest and smallest samples have a vitreous lustre and the third sample has a more pearly lustre and richer green colour. Mariposite (K(Al,Cr)2(Al,Si)4O10(OH)2) is the chromium-rich member of the mica group. Lustre is pearly or vitreous and streak is colourless. Hardness is 2 1/2 and cleavage is good. Mariposite usually occurs as massive, tabular or platy in form. https://www.mindat.org/min-10003.html https://en.wikipedia.org/wiki/Mariposite

Specifications

Object nameMariposite
IDUNB-2017-0194
Legal statusPermanent collection
CategoryMineral
Classification
Mineral group:
Silicates
Sub-group:
Phyllosilicates
Composition
  • (Al,Fe2+,Fe3+Li,Mg,Mn,Ni)5−6(Al,Fe3+,Si)4(O,OH)18
  • K(Fe,Mg)3AlSi3O10(OH)2
  • (Mg,Fe2+)5Al(Si3Al)O10(OH)8
  • Various (e.g., Muscovite - KAl2(AlSi3O10)(OH)2)
  • Al2Si2O5(OH)4
  • K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2
  • Na2AlSi3O8·H2O
  • LiAlSi4O10
  • NaAl2(AlSi3O10)(OH)2
  • D3[Si2O5](OH)4
  • Mg3(Si2O5)(OH)4
  • KAl2(AlSi3O10)(F,OH)2
OriginCalifornia, U.S.A.?
Pieces3
PartialNo
Measurements
  • 2.5cm x 8cm x 4.3cm
  • 4cm x 6cm x 3cm
  • 2cm x 5cm x 2cm