Gismondine-Sr, Sr4(Al8Si8O32)·9H2O, a new strontium dominant, orthorhombic zeolite of the gismondine series from the Hatrurim Complex, Israel

Nowak, Katarzyna; Cametti, Georgia; Galuskina, Irina O.; Vapnik, Yevgeny; Galuskin, Evgeny V. (2022). Gismondine-Sr, Sr4(Al8Si8O32)·9H2O, a new strontium dominant, orthorhombic zeolite of the gismondine series from the Hatrurim Complex, Israel (In Press). American mineralogist Mineralogical Society of America 10.2138/am-2022-8376

[img] Text
8376NowakPreprint.pdf - Accepted Version
Restricted to registered users only until 25 March 2023.
Available under License Publisher holds Copyright.

Download (2MB) | Request a copy

A new mineral, gismondine-Sr with ordered gismondine framework type (B2212 no.20, Z= 1; a = 14.0256(2) Å, b = 10.45900(10) Å, c = 13.79360(10) Å), V= 2023.44(4)Å3) and the following ideal chemical formula Sr4(Si8Al8O32)·9H2O was discovered in amygdaloidal voids of partly melted gehlenite hornfels at Halamish locality, Hatrurim Basin of the Hatrurim Complex, Negev Desert, Israel. Gehlenite hornfels is mainly composed of gehlenite, wollastonite, and garnet of the grossular-andradite-schorlomite series. In a low-temperature association occur minerals such as thomsonite-Ca, flörkeite, analcime and minerals of the tobermorite supergroup. Gismondine-Sr forms spherulitic aggregates up to 180 μm and, rarely, pseudotetragonal bipyramidal crystals up to 50 μm. Empirical crystal chemical formula of gismondine-Sr is as follows (Sr2.02Ca1.09Ba0.02K0.72Na0.62)∑4.47Al7.91Si8.09O31.85·9H2O. It is the strontium analog of gismondine-Ca and the second orthorhombic zeolite with the GIS structure topology. Crystals are transparent to translucent and feature vitreous lustre. The mineral exhibits a white color, imperfect cleavage in [101] direction, a brittle tenacity, and uneven fracture. The Mohs hardness was estimated at approximately 4. Gismondine-Sr is biaxial negative, α = 1.488(3), β = 1.492(3), γ = 1.495(3), 2Vobs = 70-80°. The Raman spectrum is characterized by a band on 465 cm-1, which is also the main band in gismondine-Ca. The structure refinement using SC-XRD (R1 = 0.0353) reveals the ordered distribution of framework cations and the disordered arrangement of extraframework cations. The aluminosilicate framework is built by crankshaft chains with 8-member apertures channels parallel to [101] and [10-1]. In gismondine-Sr, the 8-member rings are elliptically deformed and the T-O-T angle of the upward and downward tetrahedra in the double crankshaft chains is smaller compared to gismondine-Ca. Consequently, a slight rotation of the double crankshaft chains has been noticed. Similar observations have been made in partially dehydrated and the pressure-modified gismondine-Ca. The present study suggested that, in addition to high-pressure and dehydration, the elliptical deformation of the channels in GIS also arises as a consequence of the extraframework cations and H2O content. Thus, the extraframework content influences the aluminosilicate framework leading to the orthorhombic symmetry.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geological Sciences > Mineralogy
08 Faculty of Science > Institute of Geological Sciences

UniBE Contributor:

Cametti, Georgia

Subjects:

500 Science > 550 Earth sciences & geology

ISSN:

0003-004X

Publisher:

Mineralogical Society of America

Language:

English

Submitter:

Georgia Cametti

Date Deposited:

25 Mar 2022 13:34

Last Modified:

25 Mar 2022 13:34

Publisher DOI:

10.2138/am-2022-8376

BORIS DOI:

10.48350/167891

URI:

https://boris.unibe.ch/id/eprint/167891

Actions (login required)

Edit item Edit item
Provide Feedback