Orthorhombic
In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic Lattice (group), lattices result from stretching a cubic crystal system, cubic lattice along two of its orthogonal pairs by two different factors, res ...
ferroselite and its
isometric polymorph dzharkenite are
iron
Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...
selenide
A selenide is a chemical compound containing a selenium with oxidation number of −2. Similar to sulfide, selenides occur both as inorganic compounds and as organic derivatives, which are called organoselenium compound.
Inorganic selenides
Th ...
s of general formula FeSe
2 precipitated under reducing conditions in anoxic environments. They are a source of selenium in the Rocky Mountains where selenium occurrence is associated with
Upper Cretaceous
The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cret ...
shale deposits.
In the frame of safety assessment calculations made for deep disposal of high-level radioactive waste, ferroselite and dzharkenite are also considered in geochemical calculations as one of the mineral phases limiting the solubility of
Selenium-79.
Names
Dzharkenite's type locale is in the Suluchekinskoye Se-U deposit in the Dzharkenskaya Depression of the Middle Ili River,
Almaty Province, in southeastern
Kazakhstan
Kazakhstan, officially the Republic of Kazakhstan, is a landlocked country primarily in Central Asia, with a European Kazakhstan, small portion in Eastern Europe. It borders Russia to the Kazakhstan–Russia border, north and west, China to th ...
. It was discovered in 1995 and named after the depression.
Ferroselite was first reported in 1955 for an occurrence in the Ust’-Uyuk uranium deposit in
Tuva
Tuva (; ) or Tyva (; ), officially the Republic of Tyva,; , is a Republics of Russia, republic of Russia. Tuva lies at the geographical center of Asia, in southern Siberia. The republic borders the Federal subjects of Russia, federal sub ...
,
Siberia
Siberia ( ; , ) is an extensive geographical region comprising all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has formed a part of the sovereign territory of Russia and its predecessor states ...
.
[ Its name comes from the ]Latin
Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...
''ferro'' (iron) and "sel" for selenium.
See also
* Coccolithophorid, a group of marine planktonic unicellular algae fixing selenium in Upper Cretaceous chalk and shale formations
* ''Emiliania huxleyi
''Gephyrocapsa huxleyi'', also called ''Emiliania huxleyi'', is the most abundant species of coccolithophore in modern oceans found in almost all ecosystems from the equator to sub-polar regions, and from nutrient rich upwelling zones to nutr ...
'', a major species of coccolithophorid active in selenium bioconcentration
References
{{Reflist
External links
Dzharkenite (FeSe2)
on mindat.org
Dzharkenite (FeSe2)
on webmineral.com
Iron minerals
Selenide minerals
Orthorhombic minerals
Minerals in space group 58