Lópezite

From Wikipedia, the free encyclopedia
  (Redirected from Lopezite)
Jump to navigation Jump to search
Lopezite
Potassium dichromate (synthetic).jpg
General
CategorySulfate minerals (chromate)
Formula
(repeating unit)
K2Cr2O7
Strunz classification7.FD.05
Dana classification35.2.1.1 Anhydrous chromates
Crystal systemTriclinic
Crystal classPinacoidal (1)
(same H-M symbol)
Space groupP1
Identification
ColorOrange-red, red
Crystal habitGranular or spherical in small crystals on the natural environment. Prismatic on lab grown crystals.
CleavagePerfect
[010] perfect, [100] distinct, [001] distinct
Mohs scale hardness2 12
LusterVitreous
StreakLight yellow
DiaphaneityTransparent
Specific gravity2.69
PleochroismVisible
Solubilitysoluble in water
Other characteristicsHealth risks: contains the carcinogenic and mutagenic chromate ion.
References[1][2]

Lopezite is a rare red chromate mineral with chemical formula: K2Cr2O7. It crystallizes in the triclinic crystal system.[1][2]

It occurs as rare vug fillings in nitrate ores in association with tarapacáite (K2CrO4), dietzeite and ulexite in the Chilean Atacama and is reported from the Bushveld igneous complex of South Africa.[1][2] Lopezite was first described in 1937 for an occurrence in Iquique Province, Chile and named after Chilean mining engineer Emiliano López Saa (1871–1959).[1]

Most lopezite offered for sale to collectors is artificially produced.[1] Synthetic varieties also exhibit monoclinic crystals.[3]

References[edit]

  1. ^ a b c d e Lopezite data on Mindat
  2. ^ a b c Lopezite data in the Handbook of Mineralogy
  3. ^ Richard V. Gaines, H. Catherine W. Skinner, Eugene E. Foord, Brian Mason, and Abraham Rosenzweig: "Dana's new mineralogy", p. 692. John Wiley & Sons, 1997