Polarized single crystal absorption spectroscopy of the Pnam-P2 1/a transition of Ilvaite Ca(Fe2+, Fe3+)Fe2+Si2O8(OH) as measured between 300 K and 450 K

Güttler, Bernd; Salje, Ekhard K. H.; Ghose, Subrata

doi:10.1007/bf00202218

Cited by 13 publications

(2 citation statements)

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“…5). The two spectra are very similar and in agreement with the data of Mozgova & Borodaev (1965), Kräutner & Medes¸an (1969), and Güttler et al (1989) for ilvaite of various deposits. We note that some of the bands in the manganilvaite spectrum in the range 800-1100 cm -1 , commonly assigned to the asymmetric Si-O stretching vibrations in sorosilicates (Lazarev 1972), are slightly lower in intensity than those in Mn-free ilvaite.…”

Section: Physical and Optical Propertiessupporting

confidence: 90%

MANGANILVAITE, CaFe2+Fe3+(Mn, Fe2+)(Si2O7)O(OH), A NEW MINERAL OF THE ILVAITE GROUP FROM Pb Zn SKARN DEPOSITS IN THE RHODOPE MOUNTAINS, BULGARIA

Bonev

Vassileva

Zotov

et al. 2005

The Canadian Mineralogist

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Manganilvaite, CaFe 2+ Fe 3+ (Mn,Fe 2+)(Si 2 O 7)O(OH), is a new mineral species, the Mn end-member of the ilvaite group of minerals. It was found in the Pb-Zn-(Mn) skarn deposits of the central Rhodope Mountains, Bulgaria, and especially in the Ossikovo and Mogilata deposits (Madan ore district) and the Govedarnika deposit (Laki district). In the marble-hosted distal skarn-type orebodies, it is closely associated with Mn-rich clinopyroxene (hedenbergite-johannsenite) ± rhodonite, and with the products of their retrograde alteration (manganoan amphiboles and chlorites, bustamite, manganoan carbonates, quartz). The mineral is black, with a vitreous luster, brittle, with a distinct cleavage. It has Mohs hardness of 5½-6 and a micro-indentation hardness (VHN 100) of 868 kg/mm 2. The measured density D x is 3.92 g/cm 3. In refl ected light, it is opaque with moderate pleochroism, from bluish gray to grayish brown, strongly anisotropic in grayish blue to pale reddish brown colors and with red internal refl ections. It is homogeneous in BSE images and in thin sections under the IR microscope, where it is transparent. The refl ectance is low, in the range 8.3-5.7% for R min (// c) and 10.0-9.3% for R max (// a). In some cases, well-shaped dipyramidal crystals occur, with a prismatic habit along c and forms r{011}, m{110}, s{210} and o{111}. The average results of 62 and 17 electron-microprobe analyses of manganilvaite from Ossikovo and Govedarnika, respectively, are (in wt.%): MgO 0.48, 0.45;

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Section: Physical and Optical Propertiessupporting

confidence: 90%

MANGANILVAITE, CaFe2+Fe3+(Mn, Fe2+)(Si2O7)O(OH), A NEW MINERAL OF THE ILVAITE GROUP FROM Pb Zn SKARN DEPOSITS IN THE RHODOPE MOUNTAINS, BULGARIA

Bonev

Vassileva

Zotov

et al. 2005

The Canadian Mineralogist

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“…However, the Fe 2 +-and Fe 3 +-ions are not completely ordered within that double-chain of octahedra. According to Tak6uchi et al (1983) and Fe 3 + at the 8d-sites of the ilvaite structure Ghose et al 1988;Robie et al 1988), at 335 K (Gfittler et al 1989), and at 346 K ). This phase transition can be referred to an increasing disorder of Fe 2 + and Fe 3 § within the double octahedron chain with increasing temperature, which is documented by the decrease of the monoclinic angle /?…”

Section: Introductionmentioning

confidence: 98%