Gottlobite, ), is a
mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Mi ...
in the
adelite group found as isolated crystals or isometric grains of orange or orange-brown color. The size of the crystals are a half millimeter in diameter and are part of the orthorhombic crystal system. Gottlobite is the
vanadate
In chemistry, a vanadate is an anionic coordination complex of vanadium. Often vanadate refers to oxoanions of vanadium, most of which exist in its highest oxidation state of +5. The complexes and are referred to as hexacyanovanadate(III) and no ...
end member in a solid solution formed with
adelite (). Gottlobite is also part of the vanadates and arsenates group. With these characteristics, it is similar to the minerals
tangeite
Tangeite, also known as calciovolborthite, is a calcium, copper vanadate mineral with formula: CaCu(VO4)(OH). It occurs as a secondary mineral that can be found in sandstone and also in the oxidized zones of vanadium bearing deposits.
It was nam ...
and
austinite
Austinite is a member of the adelite-descloizite group, adelite subgroup, the zinc (Zn) end member of the copper-Zn series with conichalcite. It is the zinc analogue of cobaltaustinite and nickelaustinite. At one time “brickerite” was thoug ...
by X-ray diffraction methods.
Occurrence
Gottlobite is a relatively rare mineral where only a small quantity of the mineral has been found. It was first observed at the site of a long-abandoned mine on the northern slope of Gottlob hill in Friedrichroda, Thuringia, Germany by Jὒrgen Graf in August of 1996. As such, gottlobite got its name from its locality. Additionally, the German translation of "Lob" means "praise" and the German translation of "Gott" means "God", as deciphered by Google Translate. In the mine at this location, Gottlobite is found in hydrothermal veins of barite that are cutting through
conglomerate. The crystals of gottlobite can be found embedded in these barite veins or as stand-alone crystals on surrounding minerals. The associated minerals in the area are hausmannite, barite, vanadian adelite, and muscovite.
Composition
Analytical methods used on gottlobite to determine its chemical composition include energy-dispersive
X-ray spectrometry (EDX) and wavelength-dispersive X-ray spectrometry (WDX). EDX revealed the presence and quantities of elements present in the mineral, including Ca, V, As, O and small amounts of Sr. This was then measured in terms of oxides, where the weight percents were 24.98 for CaO, 0.92 for SrO, 17.54 for MgO, 1.50 for MnO, 1.44 for CuO, 27.47 for V
2O
5, 20.32 for As
2O
5, and 5.4 for H
2O. Mg is in gottlobite's chemical formula, but was not found in the EDX testing because of very similar pattern of arsenic lines that were overlapping with magnesium. The full empirical formula of gottlobite is . As seen in the formula, it was also determined that the arsenic and vanadium atoms are in 4-fold (tetrahedral) coordination with oxygen, and the magnesium atoms are in six-fold (octahedral) coordination.
See also
*
List of minerals
This is a list of minerals which have Wikipedia articles.
Minerals are distinguished by various chemical and physical properties. Differences in chemical composition and crystal structure distinguish the various ''species''. Within a mineral speci ...
References
{{reflist
External links
Gottlobit
Calcium minerals
Magnesium minerals
Vanadate minerals
Hydroxide minerals
Orthorhombic minerals
Minerals described in 2000