Johannite
Encyclopedia
Johannite is a rare uranium
sulfate mineral
. It crystallizes in the triclinic crystal system
with the chemical composition Cu[UO2(OH)SO4]2·8H2O. It crystallizes in the triclinic system and develops only small prism or thin to thick tabular crystal
s, usually occurs as flaky or spheroidal aggregates and efflorescent coatings. Its color is emerald-green to apple-green and its streak is pale green.
Johannite is a strong radioactive mineral with a calculated activity of 87,501,143 Bq
/g (to the comparison: natural potassium
: 31.2 Bq/g).
. It was named for Archduke John of Austria (1782–1859), the founder of the Landesmuseum Joanneum
(Styria, Austria).
as well as different other uranium minerals
Localities include Argentina, Czech Republic, France, Gabon, Germany, Greece, Italy, Switzerland, United Kingdom and the United States of America. Type locality
is the “Elias Mine” in Jáchymov
(Czech Republic).
P with the lattice parameters
a = 8.92 Å
, b = 9.59 Å, c = 6.84 Å; α = 110°, β = 111.98°, γ = 100.3° and one formula unit per unit cell.
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
sulfate mineral
Sulfate mineral
The sulfate minerals are a class of minerals which include the sulfate ion within their structure. The sulfate minerals occur commonly in primary evaporite depositional environments, as gangue minerals in hydrothermal veins and as secondary minerals in the oxidizing zone of sulfide mineral deposits...
. It crystallizes in the triclinic crystal system
Triclinic crystal system
thumb|180px|Triclinic In crystallography, the triclinic crystal system is one of the 7 crystal systems. A crystal system is described by three basis vectors. In the triclinic system, the crystal is described by vectors of unequal length, as in the orthorhombic system...
with the chemical composition Cu[UO2(OH)SO4]2·8H2O. It crystallizes in the triclinic system and develops only small prism or thin to thick tabular crystal
Crystal
A crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions. The scientific study of crystals and crystal formation is known as crystallography...
s, usually occurs as flaky or spheroidal aggregates and efflorescent coatings. Its color is emerald-green to apple-green and its streak is pale green.
Johannite is a strong radioactive mineral with a calculated activity of 87,501,143 Bq
Becquerel
The becquerel is the SI-derived unit of radioactivity. One Bq is defined as the activity of a quantity of radioactive material in which one nucleus decays per second. The Bq unit is therefore equivalent to an inverse second, s−1...
/g (to the comparison: natural potassium
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
: 31.2 Bq/g).
Etymology and history
Johannite was first described in 1830 by Wilhelm Karl Ritter von HaidingerWilhelm Karl Ritter von Haidinger
Wilhelm Karl Ritter von Haidinger was an Austrian mineralogist, geologist and physicist....
. It was named for Archduke John of Austria (1782–1859), the founder of the Landesmuseum Joanneum
Landesmuseum Joanneum
The Universalmuseum Joanneum is a multidisciplinary museum in Styria, Austria. It has galleries and collections in many subject areas including Archaeology, Geology, Palaeontology, Mineralogy, Botany, Zoology, History, Art and Folk Culture...
(Styria, Austria).
Occurrence
Johannite forms as secondary mineral by oxidation from uraniniteUraninite
Uraninite is a radioactive, uranium-rich mineral and ore with a chemical composition that is largely UO2, but also contains UO3 and oxides of lead, thorium, and rare earth elements...
as well as different other uranium minerals
Localities include Argentina, Czech Republic, France, Gabon, Germany, Greece, Italy, Switzerland, United Kingdom and the United States of America. Type locality
Type locality (geology)
Type locality , also called type area or type locale, is the where a particular rock type, stratigraphic unit, fossil or mineral species is first identified....
is the “Elias Mine” in Jáchymov
Jáchymov
For other places called Joachimsthal, see Joachimsthal Jáchymov . compl: "Sant Joachim's Sthal" is a spa town in north-west Bohemia in the Czech Republic belonging to the Karlovy Vary Region. It is situated at an altitude of 733 m above sea level in the eponymous St...
(Czech Republic).
Crystal structure
Johannite crystallizes in the triclinic crystal system in the space groupSpace group
In mathematics and geometry, a space group is a symmetry group, usually for three dimensions, that divides space into discrete repeatable domains.In three dimensions, there are 219 unique types, or counted as 230 if chiral copies are considered distinct...
P with the lattice parameters
Lattice constant
The lattice constant [or lattice parameter] refers to the constant distance between unit cells in a crystal lattice. Lattices in three dimensions generally have three lattice constants, referred to as a, b, and c. However, in the special case of cubic crystal structures, all of the constants are...
a = 8.92 Å
Ångström
The angstrom or ångström, is a unit of length equal to 1/10,000,000,000 of a meter . Its symbol is the Swedish letter Å....
, b = 9.59 Å, c = 6.84 Å; α = 110°, β = 111.98°, γ = 100.3° and one formula unit per unit cell.