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| twinning = Not observed
| twinning = Not observed
| fracture = Conchoidal to irregular
| fracture = Conchoidal to irregular
| tenacity = Brittle
| mohs = 4.5
| mohs = 4.5
| luster = Vitreous to adamantine
| luster = Vitreous to adamantine
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| pleochroism = Medium strong with X = orange-brown, Y = pale yellowish brown, and Z = orange-brown
| pleochroism = Medium strong with X = orange-brown, Y = pale yellowish brown, and Z = orange-brown
| streak = Light brownish
| streak = Light brownish
| gravity = 3.46
| gravity = 3.46 g/cm<sup>3</sup> (calculated)
| melt =
| melt =
| fusibility =
| fusibility =
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| solubility =
| solubility =
| diaphaneity = Transparent
| diaphaneity = Transparent
| other = Brittle
| other =
| references = <ref>[http://webmineral.com/data/Gottlobite.shtml#.WhhKL7Q-dE4 Gottlobite]. Webmineral. Retrieved on 2017-11-24.</ref><ref> <ref name=Witzke>{{cite journal|last1=Witzke|first1=T.|last2=Steins|first2=M.|last3=Doering|first3=T.|last4=Kolitsch|first4=U.|title=Gottlobite, CaMg(VO4, AsO4)(OH), a new mineral from Friedrichroda, Thuringia, Germany|journal=Neues Jahrbuch fur Mineralogie. Monatshefte.|date=2000|volume=Monatshefte 2000|pages=444-454|accessdate=23 November 2017}}</ref>}}
| references = <ref>[http://webmineral.com/data/Gottlobite.shtml#.WhhKL7Q-dE4 Gottlobite]. Webmineral. Retrieved on 2017-11-24.</ref><ref> <ref name=Witzke>{{cite journal|last1=Witzke|first1=T.|last2=Steins|first2=M.|last3=Doering|first3=T.|last4=Kolitsch|first4=U.|title=Gottlobite, CaMg(VO4, AsO4)(OH), a new mineral from Friedrichroda, Thuringia, Germany|journal=Neues Jahrbuch fur Mineralogie. Monatshefte.|date=2000|volume=Monatshefte 2000|pages=444-454|accessdate=23 November 2017}}</ref>}}



Revision as of 17:17, 28 November 2017

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Gottlobite
General
CategoryHydroxide mineral
Formula
(repeating unit)
CaMg(VO4, AsO4)(OH)
Strunz classification08.BH.35
Dana classification41.05.01.10
Crystal systemOrthorhombic
Space groupP222
Unit cella = 7.501(4) Å; b = 9.010(7) Å; c = 5.941(4) Å; Z = 4, V = 401.5Å3
Identification
Formula mass205.20 gm
ColorOrange to orange-brown
Crystal habitIsometric to tabular crystals
TwinningNot observed
CleavageNot observed
FractureConchoidal to irregular
TenacityBrittle
Mohs scale hardness4.5
LusterVitreous to adamantine
StreakLight brownish
DiaphaneityTransparent
Specific gravity3.46 g/cm3 (calculated)
Optical propertiesBiaxial negative
Refractive indexnα = 1.797 nβ = 1.805-1.815 nγ = 1.828
PleochroismMedium strong with X = orange-brown, Y = pale yellowish brown, and Z = orange-brown
References[1]Cite error: A <ref> tag is missing the closing </ref> (see the help page).


Gottlobite CaMg(VO4,AsO4)(OH) is a mineral found as isolated crystals or isometric grains of orange or orange-brown color. The maximum size of the crystals are a half millimeter and are part of the orthorhombic crystal system. Gottlobite is isostructural with adelite and is part of the vanadates and arsenates group. With these characteristics, it is similar to the minerals tangeite and austinite by x-ray diffraction methods. [2]

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 this mine, 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. [2]

Chemical and crystal properties

Analytical methods used on gottlobite to determine its chemical qualities include energy-dispersive x-ray spectrometry (EDX) and wavelength-dispersive x-ray spectrometry (WDX). The EDX revealed the presence and quantities of elements present in the mineral, including Ca, V, As, O and small amounts of Sr. Mg is in gottlobite's chemical formula, but was not found in the EDX testing because of the very similar arsenic (As) lines that were overlapping with magnesium (Mg). It was also determined that the arsenic (As) and vanadium (V) atoms are in tetrahedral coordination with oxygen (O), and the magnesium (Mg) atoms are in octahedral coordination. [2]



See also

References

  1. ^ Gottlobite. Webmineral. Retrieved on 2017-11-24.
  2. ^ a b c Cite error: The named reference Witzke was invoked but never defined (see the help page).