Grunerite Research Articles

Colorado Artist Susan A. Judy (b. 1955)

Figure 1. Wing on the Wind, 2018; 19.75″ × 25″; grunerite, silicified porcelanite, amethyst, other slabs, and apophyllite on stilbite.Reproduced with permissionFigure 2. Enemy Within: Mt. Erebus Vo...

The crystal structure of mineral fibres. 2. Amosite and fibrous anthophyllite

This study reports for the first time crystal-structure data for amosite and fibrous anthophyllite. The chemical composition of the two fibre species was determined from EMPA. Crystal structures were refined using powder-diffraction data, using both laboratory sources and synchrotron radiation. Results were compared with the available literature data for the non-fibrous varieties grunerite and anthophyllite, respectively. The calculated site-occupancies for all samples are in agreement with the chemical compositions calculated from EMPA. The existing structure models of grunerite and orthorhombic anthophyllite also applies to the corresponding fibrous varieties amosite and fibrous anthophyllite, respectively. In amosite, both Fe2+ and Fe3+ atoms are found at the sites M(1), M(2) and M(3) and Fe2+ ions is the only atomic species found at site M(4). Mg is disordered over the C sites with a preference for site M(2). Minor Ca and Na have been assigned to the A site. In fibrous anthophyllite, Mg is the only atomic species found at the M1, M2 and M3 sites. Fe2+, Mg (and minor Mn) have been assigned to the M4 site, whereas minor Ca has been assigned to the A site. In both structures, the environment at the M(4) site in amosite and M4 site is in fibrous anthophyllite highly distorted. This work can be considered a basis for studies aimed at understanding the potential toxicity/pathogenicity of these mineral fibres.

Characterization of minerals in pleural plaques from lung tissue of nonhuman primates

Periodico di Mineralogia (2011), 80, 1 (Special Issue), 167-179 - DOI: 10.2451/2011PM0014 Special Issue in memory of Sergio Lucchesi Characterization of minerals in pleural plaques from lung tissue of non-human primates Anne E. Taunton 1 , Mickey E. Gunter 1, 2,* , Robert P. Nolan 3 and James I. Phillips 4 1 Department of Geological Sciences, University of Idaho, Moscow, Idaho, USA 2 Marsh Professor-at-Large, University of Vermont, Burlington, Vermont, USA 3 Earth and Environmental Sciences of the Graduate School and University Center of The City University of New York, New York, USA 4 Pathology Division, National Institute for Occupational Health, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences,University of Witwatersrand, Johannesburg, South Africa *Corresponding author: mailto:mgunter@uidaho.edu Abstract To examine the hypothesis that secondary minerals precipitate in the lung after the inhalation of fibrous minerals, pleural plaques from 11 non-human primates (NHP) were examined using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and powder X-ray diffraction (XRD). Two NHPs served as controls, and nine were exposed to either low (1 f/cc) or high (1000 f/cc) levels of chrysotile, asbestiform grunerite (amosite), asbestiform riebeckite (crocidolite), or glass fibers. XRD analysis revealed apatite in pleural plaques of six NHPs, and SEM-EDS analysis found small quantities of apatite in three additional NHPs. XRD analysis identified calcite in one control NHP and one exposed to chrysotile (with talc present) and in the NHPs exposed to high doses of glass fibers, chrysotile, and grunerite. XRD analysis detected 2:1 expandable clays in NHPs exposed to high levels of glass fibers, chrysotile, grunerite and riebeckite. XRD also detected amphiboles in NHPs exposed to high levels of grunerite and riebeckite. SEM-EDS analysis revealed Mg-rich silicates in a control NHP and one NHP exposed to low doses of chrysotile. Asbestos bodies coating fibers were detected in NHPs exposed to high levels of grunerite and chrysotile. Iron-rich silicate fibers without coatings were identified in the NHP exposed to high levels of riebeckite using SEM-EDS. SEM-EDS also revealed Na-rich silicates in one NHP exposed to low doses of chrysotile. Because minerals other than exposure minerals were detected in many of the NHPs, the hypothesis that secondary minerals may form in the lung after exposure to fibrous minerals should be considered when addressing the health effects of minerals. Key words : asbestos; in vivo; SEM; powder X-ray diffraction; pleural plaques.

High-pressure transformation behaviour of the cummingtonite-grunerite solid solution

The displacive C2/m ⟷ P2 1 /m phase transition that occurs with increasing pressure in cummingtonites has been investigated by means of X-ray single-crystal diffraction at different compositions and degrees of Mg/Fe 2+ order. Unit-cell parameters and a sub-set of intensity data of some “ b ” and “ a ” reflections were collected for four natural and two annealed samples as a function of pressure. The phase transition is close to second order in character, either with a significant contribution from the sixth order term of the Landau potential or with the fourth order coefficient depending on pressure via the bare elastic constants. The transition pressure, P c , obtained at the different compositions and degrees of order, displays a plateau at the grunerite end. The evolution of the spontaneous strain associated with the phase transition does not depend on the Mg/Fe 2+ substitution or ordering, but it is very sensitive to the impurity (Al, Na, Ca) content.

Stability relations of grunerite, Fe 7 Si 8 O 22 (OH) 2

Stability relations of grunerite, Fe 7 Si 8 O 22 (OH) 2

Helvite and Tourmaline Accompanied by Grunerite in Quartz

Helvite and Tourmaline Accompanied by Grunerite in Quartz