Lópezite Explained

Lópezite
Category:Sulfate minerals (chromate)
Formula:K2Cr2O7
Imasymbol:Lpz[1]
Strunz:7.FD.05
Dana:35.2.1.1 Anhydrous chromates
System:Triclinic
Class:Pinacoidal
(same H-M symbol)
Symmetry:P
Color:Orange-red, red
Habit:Granular or spherical in small crystals on the natural environment. Prismatic on lab grown crystals.
Cleavage:Perfect
[010] perfect, [100] distinct, [001] distinct
Luster:Vitreous
Streak:Light yellow
Diaphaneity:Transparent
Gravity:2.69
Pleochroism:Visible
Solubility:soluble in water
Other:Health risks: contains the carcinogenic and mutagenic chromate ion.

Lópezite is a rare red chromate mineral with chemical formula: K2Cr2O7. It crystallizes in the triclinic crystal system.[2] [3]

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.[2] [3] Lópezite was first described in 1937 for an occurrence in Iquique Province, Chile and named after Chilean mining engineer Emiliano López Saa (1871–1959).[2]

Most commercially available lópezite is artificially produced.[2] Synthetic varieties also exhibit monoclinic crystals.[4]

Notes and References

  1. Warr. L.N.. 2021. IMA–CNMNC approved mineral symbols. Mineralogical Magazine. 85. 3. 291–320. 10.1180/mgm.2021.43. 2021MinM...85..291W. 235729616. free.
  2. http://www.mindat.org/min-2433.html Lópezite data on Mindat
  3. http://rruff.geo.arizona.edu/doclib/hom/lopezite.pdf Lópezite data in the Handbook of Mineralogy
  4. 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