The Crystal Chemistry of Epistolite

Sokolova, Elena; Hawthorne, Frank C.

doi:10.2113/gscanmin.42.3.797

Cited by 42 publications

(39 citation statements)

References 5 publications

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“…The NbO 6 octahedron is essentially distorted with one short (1.770 Å) Nb-O5 bond opposite to one long Nb-O w 1 (2.29 Å) bond, and four intermediate (~1.98 Å) Nb-O bonds. This kind of octahedral distortion is typical for NbO 6 octahedra in H sheets and was observed, for instance, in vuonnemite, Na 11 [37], two minerals most closely related to shkatulkalite (see below). The refined SSF of the Ti site is close to 22 e − , which would account for the full occupancy of this site by Ti.…”

Section: Resultsmentioning

confidence: 66%

“…More precisely, shatulkalite is a member of the lamprophyllite group, having Ti + (Nb + Mn) = 3 apfu, from which the H and O sheets has 2 and 1 (Ti + Nb + Mn) apfu, respectively. The most closely related species to shkatulkalite are vuonnemite, Na 11 4 [37,38], crystal structures of which are shown in Figure 3b,c, respectively. The three minerals are based upon the same topological type of the HOH blocks (Figure 2b-d) with different layer symmetries (p2/m in shkatulkalite, and p − 1 in vuonnemite and epistolite).…”

Section: Discussionmentioning

confidence: 99%

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Shkatulkalite, a Rare Mineral from the Lovozero Massif, Kola Peninsula: A Re-Investigation

et al. 2018

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Abstract:The crystal structure of shkatulkalite has been solved from the crystal from the Lovozero alkaline massif, Kola Peninsula, Russia. The mineral is monoclinic, P2/m, a = 5.4638(19), b = 7.161(3), c = 15.573(6) Å, β = 95.750(9) • , V = 606.3(4) Å 3 , R 1 = 0.080 for 1551 unique observed reflections. The crystal structure is based upon the HOH blocks consisting of one octahedral (O) sheet sandwiched between two heteropolyhedral (H) sheets. The blocks are parallel to the (001) plane and are separated from each other by the interlayer space occupied by Na1 atoms and H 2 O groups. The Na2, Na3, and Ti sites are located within the O sheet. The general formula of shkatulkalite can be written as Na 5 (Nb 1−x Ti x ) 2 (Ti 1−y Mn 2+ y )[Si 2 O 7 ] 2 O 2 (OH) 2 ·nH 2 O, where x + y = 0.5 and x ≈ y ≈ 0.25 for the sample studied. Shkatulkalite belongs to the seidozerite supergroup and is a member of the lamprophyllite group. The species most closely related to shkatulkalite are vuonnemite and epistolite. The close structural relations and the reported observations of pseudomorphs of shkatulkalite after vuonnemite suggest that, at least in some environments, shkatulkalite may form as a transformation mineral species.

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Section: Resultsmentioning

confidence: 66%

Section: Discussionmentioning

confidence: 99%

Shkatulkalite, a Rare Mineral from the Lovozero Massif, Kola Peninsula: A Re-Investigation

et al. 2018

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“…Sokolova et al (2000) pointed out that dehydroxylated amphiboles with OH + F < 2 apfu and significant Ti 4+ and Fe…”

Section: T(1)mentioning

confidence: 99%

“…Constructive reviews by Prof. S. Kobayashi and Dr. [4] Al and Cl of K -rich calcic amphiboles with [4] Al ≥ 1.5 apfu and [A] (Na + K) ≥ 0.5 apfu. The chemical data are from Borley (1963), Krutov and Vinogradova (1966), Leelanandam (1970), Czamanske et al (1977), Hawthorne and Grundy (1977), Dick and Robinson (1979), Sharma (1981), Shimazaki et al (1984), Matsubara and Motoyoshi (1985), van Marcke de Lummen and Verkaeren (1985), Gulyaeva et al (1986), Suwa et al (1987), Sawaki (1989), Morrison (1991), Enami et al (1992), Oberti et al (1993), Shira ishi et al (1994, Deer et al (1997), Robinson et al (1997), Sato et al (1997), Sokolova et al (2000), Chukanov et al (2002), Mazdab (2003), Banno et al (2004), Pekov et al (2005), Korinevskiy and Korinevskiy (2006), Sautter et al (2006) and Banno et al (this study). The Cl contents of K -rich amphiboles described by Shimazaki et al (1984) and Sawaki (1989) were not given, but they pointed out that qualitative analyses of these amphiboles show no appreciable amount of chlorine.…”

Section: Acknowledgmentsmentioning

confidence: 99%

Potassic-ferropargasite, a new member of the amphibole group, from Kabutoichiba, Mie Prefecture, central Japan

Banno

Miyawaki

Matsubara

et al. 2009

Journal of Mineralogical and Petrological Sciences

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(OH) 2 , is a new member of the amphibole group occurring in a schistose calcareous hornfels from Kabutoichiba, Kameyama, Mie Prefecture, central Japan. The amphibole occurs as black subhedral to anhedral crystals, up to about 700 µm long, associated with calcite, biotite, K -feldspar, plagioclase, scapolite, chlorite and titanite. Potassic -ferropargasite is optically biaxial negative with α = 1.680(2), β = 1.690 (calc.), γ = 1.698 (2) (100) Σ2.00 on the basis of O = 23, assuming OH + F + Cl = 2. The crystal structure of the clinoamphibole type was refined to an R of 6.5%.

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“…98 (Sokolova and Hawthorne, 2004), gives a twin with twin plane (001). The direction perpendicular to this plane is: …”

Section: The Twin Lattice Of Twofold Twins In Case Of Tlqsmentioning

confidence: 99%

Geminography: the crystallography of twins

Grimmer¹,

Nespolo

2006

Zeitschrift Für Kristallographie - Crystalline Materials

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Abstract. The geometric theory of twinning was developed almost a century ago. Despite its age, it still represents the fundamental approach to the analysis and interpretation of twinned crystals, in both the direct and the reciprocal space. In recent years, this theory has been extended not only in its formalism (group-subgroup analysis, chromatic symmetry) but also in its classification of special cases that were not recognized before. The geometrical theory of twinning is thus reviewed here with emphasis on lattice aspects and recent developments. The classification of various types of twins starts with Friedel's well-known scheme, which distinguishes four cases according to whether the twin index n is equal to or larger than 1 and whether the obliquity w is equal to or larger than 0: the computation of these quantities is discussed in detail. It is shown that the concept of obliquity is not sufficient to characterize the pseudo-symmetry of a lattice, and the consequent twinning, in the case of manifold twins. The application of the theory of coincidence-site lattices to twinning is presented. Finally, the effect of twinning on the diffraction pattern is illustrated with a number of examples.

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The Crystal Chemistry of Epistolite

Cited by 42 publications

References 5 publications

Shkatulkalite, a Rare Mineral from the Lovozero Massif, Kola Peninsula: A Re-Investigation

Shkatulkalite, a Rare Mineral from the Lovozero Massif, Kola Peninsula: A Re-Investigation

Potassic-ferropargasite, a new member of the amphibole group, from Kabutoichiba, Mie Prefecture, central Japan

Geminography: the crystallography of twins

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