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MSH News |
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Table of Contents - Announcements - Court Saunders - Liz Fodi - Michael Skebo - Ronnie van Dommelan - Tony Steede reprinted from Walker Mineralogical Club - Malcolm Back - László Horváth - Bob Gault - Abstracted by Malcolm Back - Bill Lechner - Josef Vajdak reprinted from Mineral News - Gary McWilliams reprinted from Mineral News New species list and more analysis - Malcolm Back Microprobe samples of the zeolites from MSH have been prepared and once thay have been probed we will be able to redesignate the zeolites to correspond to the new nomenclature published in 1997. We will also publish an updated species list.  Thorbastnasite found at MSH - László Horváth Thorbastnäsite was found in the Poudrette pegmatite, on level 8 in July and August last year (1998) by Robin Tibbit and Bob Rothenberg. It occurred in vuggy pegmatite rocks associated mainly with albite, siderite, röntgenite-(Ce) and nenadkevichite. Other associated minerals are natrolite, rutile and beige granular aggregates of what appears to be altered rhodochrosite. The thorbastnäsite forms the cores of numerous opaque, white rod-like aggregates, 0.3-1.5 mm long. The rods are encrusted by minute (<0.1 mm) hexagonal tabular crystals of röntgenite-(Ce) totally covering the thorbastnäsite. It is unlikely that the core of these rods is a single prismatic crystal of thorbastnäsite. The röntgenite-(Ce) was identified by Andy McDonald and the thorbastnäsite by Tony Nikischer. The type locality for thorbastnäsite is the Pichikhol alkaline massif, Tuva, Siberia in Russia. MSH is the second Canadian locality for the mineral, the first is the Francon quarry in Montreal. Other known localities are also alkaline complexes such as Point of Rocks, New Mexico, USA and Poços de Cladas, Minas Gerais, Brazil. We only have two small specimens and the list of associated minerals is probably more extensive. UK 96 = UK 106 = ? - Bob Gault This new mineral currently designated as UK96 and UK106 has been submitted and approved as a new mineral. The paper on the new mineral is being prepared for publication. The name will be released when it is published. The new, triclinic mineral from MSH has the formula NaY(CO3)2 • 6H2O; is colourless to white, sometimes pale pink, transparent to translucent, with a vitreous lustre. It occurs as flattened, acicular to fibrous crystals to 2.5 cm in length and usually forms spherical groups of radiating crystals; non fluorescent; cleavage {001} perfect, {100} and {010} good. The mineral is brittle with a Mohs hardness of 3. It effervesces vigorously in 10% HCl. The 6 strongest X-ray lines are: 12.81 (100) (001), 6.45 (70) (002), 4.456 (60) (12, 120), 4.291 (60) (003), 2.571 (60) (043), 2.050 (50) (16, 160). It was found in a large alkaline pegmatite dike in the south corner of the Poudrette quarry, Mont Saint-Hilaire, Quebec. This dike has been exposed on levels 7, 8 and 9. The mineral was first collected by Gilles Haineault in 1992 and was designated as UK 96. A good deal of material was collected in 1998 by various collectors including, the Horváths (who provided me with the complete list of associated species), Peter Tarassoff who provided us with what became the type material (and which we had designated as UK 106) and members of the 1998 IMA field trip. It occurs as a very late-stage, low temperature, hydrothermal phase in cavities in an alkaline pegmatite dike in nepheline syenite, associated with a large number of species including (in no particular order) molybdenite, franconite, calcite, siderite, rhodochrosite, microcline, albite, aegirine, analcime, natrolite, kupletskite, catapleiite, gonnardite, eudialyte, sabinaite, nenadkevichite, narsarsukite, fluorite, pyrochlore, donnayite-(Y), elpidite, serandite, genthelvite, leifite, epididymite, eudidymite, polylithionite, horváthite, thomasclarkite-(Y) (sometimes as epitactic overgrowths on UK96- UK106), sphalerite, galena, petersenite-(Ce), gaidonnayite, quartz.
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