From Wikipedia, the free encyclopedia
Jump to: navigation, search
Coccinite, from Backofen Mine, Rhineland-Palatinate, Germany
Category Halide mineral
(repeating unit)
Strunz classification 3.AB.10
Crystal system Tetragonal
Crystal class Ditetragonal dipyramidal (4/mmm)
H-M symbol: (4/m 2/m 2/m)
Space group P42/nmc
Unit cell a = 4.376 Å, c = 12.41 Å, Z = 2
Colour Orange-red
Cleavage Good on {001}
Mohs scale hardness 2
Streak Orange
Diaphaneity Translucent
Specific gravity 3.17 (calculated)
Optical properties Uniaxial (-)
Refractive index 2.684 (avg)
Birefringence 0.193
Other characteristics Volatile at room temperature
References [1][2][3]

Coccinite is a rare mercury iodide mineral with chemical formula of HgI2, mercury(II) iodide.[4][5] in addition to its discovery locality of Casas Viejas, Mexico, it has also been reported from Broken Hill, New South Wales, and from a uranium mine in Thuringia and old mercury workings in the Rhineland-Palatinate in Germany.[1] At the Thuringia deposit the mineral occurs as a sublimation product resulting from fires associated with pyrite bearing, graptolitic slate.[5]


The discovery was announced by del Rio in the journal of the Mexico city School of Mining. The news spread by reading that journal and a direct letters of del Rio. In the subsequent years several times the discovery was mentioned. One of the earliest notes of the discovery is a translation of a letter of del Rio to Freiesleben.[citation needed] In 1839 it was described as lemon coloured spots in the sandstone of Casas Vijecas.[6] This description was also given in a Spanish book printed in 1844.[7] In 1836 a short paper was published in Comptes rendus which was the communication of Yniestra to Arago about a discovery of del Rio. In this publication the mineral sample was deposited at the school of mines by a Mr. Jose Casas Viejas from the Querétaro province and that the mineral had a red brown colour.[8] In 1861 the book A glossary of mineralogy by Henry William Bristow states that it has been found in Casas Viejas in Mexico as reddish brown particles on mercury selenide.[9] Shortly after in 1862 a book about chemical technology gives the only location where the mineral can be found with a Mexican region Cavas Viejas.[10]


  1. ^ a b Coccinite on
  2. ^ Coccinite data on Webmin
  3. ^ Coccinite on Mineral Atlas
  4. ^ Witzke, T. (1997). "New data on the mercury iodide mineral coccinite, HgI2". Neues Jahrbuch für Mineralogie - Monatshefte: 505–510. 
  5. ^ a b Jambor, John; Pertsev, Nicolai; Roberts, Andrew (1998). "New Mineral Names" (PDF). American Mineralogist. 83: 907–910. 
  6. ^ Britain), Society for the Diffusion of Useful Knowledge (Great (1839). The Penny cyclopædia of the Society for the Diffusion of Useful Knowledge. 
  7. ^ Domeyko, Ignacio (1844). Tratado de ensayes, tanto por la via seca como por la via humeda, de toda clase de minerales y pastas de cobre, plomo, plata, oro, mercurio, &c: con descripcion de los caracteres de los principales minerales y productos de las artes en America, y en particular en Chile. 
  8. ^ "Une nouvelle combinaison naturelle de l'iode". Comptes rendus: 582–583. 1836. 
  9. ^ Bristow, Henry William (1861). A glossary of mineralogy. 
  10. ^ Richardson, Thomas (1863). Chemical technology; or, Chemistry in its applications to the arts & manufactures. 

External links[edit]