Marshite (CuI) is a naturally occurring
isometric halide mineral with occasional
silver
Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical ...
(Ag) substitution for
copper
Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...
(Cu).
[Prior, G.T. (1902]
“The identity of kilbrickenite with geocronite: And analyses of miersite, marshite, and copper-pyrites”
''Mineralogical Magazine'', 13: 186–190.[Palache, C., Berman, H., Frondel, C. (1951) "''The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana Yale University 1837-1892, Volume II: Halides, Nitrates, Borates, Carbonates, Sulfates, Phosphates, Arsenates, Tungstates, Molybdates, Etc."'' John Wiley and Sons, Inc., New York, 7th edition, revised and enlarged: pp. 20-22.] Solid solution between the silver end-member miersite and the copper end-member marshite has been found in these minerals from deposits in
Broken Hill,
Australia.
[Millsteed, P.W. (1998]
“Marshite - miersite solid solution and iodargyrite from Broken Hill, New South Wales, Australia“
''Mineralogical Magazine'', 62(4): 471–475. The mineral's name is derived from the person who first described it, an Australian mineral collector named Charles W. Marsh.
[Handbook of Mineralogy - Marshite]
/ref>
/ref>[Webmineral - Marshite]
/ref> Marsh drew attention to native copper iodide (Marshite) in the 1800s emphasizing its natural occurrence, it is not to be confused with copper (I) iodide a substance commonly synthesized in laboratory settings.[Marsh, C.W. (1892) ''Proceedings of the Royal Society of New South Wales'', 26: 326–332 (as Native copper iodide).][Marsh, C.W. and Liversidge, A. (1892) "On Native Copper Iodide (Marshite) and other Minerals from Broken Hill, N.S. Wales", ''Journal and Proceedings of the Royal Society of New South Wales'', 26: 326–332.]
One of marshite's distinguishing features is that prior to exposure to air the mineral is a faint honey
Honey is a sweet and viscous substance made by several bees, the best-known of which are honey bees. Honey is made and stored to nourish bee colonies. Bees produce honey by gathering and then refining the sugary secretions of plants (primar ...
-yellow color, once exposed to the air however it becomes a brick-red color.[ Another characteristic useful in identifying marshite is the dark red color it fluoresces under short-wave (SW) and long-wave (LW) ]ultraviolet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation ...
light.[
]
Geologic occurrence
The type locality of marshite is a metamorphosed Lead-Zinc-Silver ore
Ore is natural rock or sediment that contains one or more valuable minerals, typically containing metals, that can be mined, treated and sold at a profit.Encyclopædia Britannica. "Ore". Encyclopædia Britannica Online. Retrieved 7 Apr ...
deposit at Broken Hill, Yancowinna County, New South Wales
)
, nickname =
, image_map = New South Wales in Australia.svg
, map_caption = Location of New South Wales in AustraliaCoordinates:
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, es ...
, Australia.cuprite
Cuprite is an oxide mineral composed of copper(I) oxide Cu2O, and is a minor ore of copper.
Its dark crystals with red internal reflections are in the isometric system hexoctahedral class, appearing as cubic, octahedral, or dodecahedral forms, ...
, and cerussite
Cerussite (also known as lead carbonate or white lead ore) is a mineral consisting of lead carbonate (PbCO3), and is an important ore of lead. The name is from the Latin ''cerussa'', white lead. ''Cerussa nativa'' was mentioned by Conrad Gessner ...
.Chuquicamata
Chuquicamata ( ; referred to as Chuqui for short) is the largest open pit copper mine in terms of excavated volume in the world. It is located in the north of Chile, just outside Calama, at above sea level. It is northeast of Antofagasta and ...
, Chile
Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...
which are heavily mined for copper.[Jarrell, O.W. (1939]
“Marshite and other minerals from Chuquicamata, Chile“
''American Mineralogist'', 24(10): 629–635. Additional research on the rocks and minerals from this area show that iodine isotopes found in minerals, such as marshite, and soil
Soil, also commonly referred to as earth or dirt
Dirt is an unclean matter, especially when in contact with a person's clothes, skin, or possessions. In such cases, they are said to become dirty.
Common types of dirt include:
* Debri ...
s can be used to understand the processes that formed the supergene deposit.[Reich, M., Snyder, G.T., Álvarez, F., Pérez, A., Palacios, C., Vargas, G., Cameron, E.M., Muramatsu, Y. and Fehn, U. (2013]
“USING IODINE ISOTOPES TO CONSTRAIN SUPERGENE FLUID SOURCES IN ARID REGIONS: INSIGHTS FROM THE CHUQUICAMATA OXIDE BLANKET“
''Economic Geology'', 108(1): 163–171.
In addition to multiple occurrences in Australia and Chile, marshite has been found and reported in Finland
Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of B ...
, Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
, Russia
Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eig ...
, and South Africa
South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. It is bounded to the south by of coastline that stretch along the Atlantic Ocean, South Atlantic and Indian Oceans; to the ...
.[ At the Rubtsovsky locality in Altai Krai, Russia marshite is found associated with other iodine-rich halide minerals such as miersite in a base metal deposit.][Pekov, I.V., Lykova, I.S., Bryzgalov, I.A., Ksenofontov, D.A., Zyryanova, L.A., and Litvinov, N.D. (2010) “Extremely rich iodide mineralization at the Rubtsovskoe base metal deposit (North West Altay, Russia) and its genesis”, ''20th General Meeting of the IMA (IMA2010)'', Budapest, Hungary, August 21–27, CD of Abstracts, p. 416.] Marshite is found in the silver deposit mined at the Albert Silver Mine in Mpumalanga, South Africa associated with various silver-rich minerals.[Meulenbeld, P.M.P.B., Grote, W., and Verryn, S. (2014]
“The Albert Silver Mine and Trippkeite Occurrence, Mpumalanga, South Africa“
''Rocks & Minerals'', 89: 416–423.
References
{{reflist
Bibliography
*Palache, P.; Berman H.; Frondel, C. (1960). "''Dana's System of Mineralogy, Volume II: Halides, Nitrates, Borates, Carbonates, Sulfates, Phosphates, Arsenates, Tungstates, Molybdates, Etc. (Seventh Edition)"'' John Wiley and Sons, Inc., New York, pp. 20–22.
Halide minerals