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MSH News |
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Table of Contents - Mike Skebo & Gary Glenn - Liz Fodi - Liz Fodi - Quintin Wight - Malcolm Back - Percy Hornblow Review of Fall Workshop 2000 - Liz Fodi The CMMA Fall Workshop, held on November 18th, 2000, provided participants with an unparalleled opportunity to examine their specimens from the Poudrette Quarry, Mont Saint-Hilaire, Québec in the company of fellow enthusiasts. The giveaway table wasn't limited to MSH specimens, though a box of pale fine-grained rock, collected in 1999 from the contact zone between the hornfels and pegmatite vein, became a prime target as excellent specimens of gmelinite, gobbinsite, analcime, molybdenum, donnayite, apatite, ferro-columbite, quartz, corundum, etc. came to light with the used of splitters provbided by Percy Hornblow. Another box, however, contained excellent specimens of reverse sceptre quartz, also known as "pagoda" quartz, from Gila River, Grant Co, New Mexico. These were collected by Mike Skebo and Phil Evanoff last November. There were also a carton of green grossular and diopside from the Orford Nickel Mine, canton d'Orford, Québec. Gary Glenn brought in a boxed display of specimens collected on a trip taken to the southwestern United States in September of this year. Clusters of willemite crystals on a Tuscan red matrix, the rich orange staining on some of the clusters providing a pleasing counterpoint to the dark background, came form the Mahoney Mine, Tres Hermans Mts, Luna Co., New Mexico. Large single crystals of bixbyite showing trisoctahedral faces and lustrous cassiterite from Paramount Canyon, Sierra Co, New Mexico illustrated perfection in form and subtle nuances caused by surface reflection. There were pretty specimens of heulandite & stilbite from Gila River near Gila Cliff Dwellings, New Mexico, aurichalcite, rosasite spheres & hemimorphite from Vesley Mine, Granite Gap, Hidalgo Co., New Mexico, and mixite, hemimorphite from Montgomery Mine, Granite Gap, Hidalgo Co., New Mexico. Cyanotrichite from White Canyon #1 Mine, Fry Mesa, Utah, and topaz crystals from Grants Ridge, Grants, New Mexico, completed the suite. But the emphasis of the workshop was on MSH and at the end of the review there is a preliminary listing of the species identified from this year's collected material. Corrections and additional information are welcome and will be published in future issues.  Notes on MSH - Quintin Wight On the May trip to Mont Saint-Hilaire, I picked up a piece of nondescript pegmatite - mostly albite, a black splintery amphibole which is probably arfvedsonite, and some rather dull rhodochrosite. It had a small cluster of tiny, yellow, hexagonal crystals, rather like very small sabinaite crystals. "Small", in this case, means at least 40X for a decent view. "Like sabinaite" means having the appearance of tiny, yellow, mica plates with striations on the edges perpendicular to the "c" axis. Think of very tiny, honey - coloured plates, almost circular in shape (there isn't space to develop the hexagon properly). I passed them to the Canadian Museum of Nature staff for a quick check, and got the word back yesterday - quintinite-3T. As far as I know, that's the first that has been seen in a long time. The specimen came from near the South corner, but I had it wrapped with a lot of others, so it's difficult to be very precise. Still, you might want to pay particular attention to anything that you picked up earlier this year. MSH Basics Arfvedsonite differs from aegirine quite strongly. In general, the prisms of arfvedsonite are much shorter. Because arfvedsonite is an amphibole, it has a diamond - shaped cross-section, while aegirine, as a pyroxene, has a relatively square one. Arfvedonite also has a habit of etching through the prism, resulting in a splintery skeleton, but often leaving the "c" face unscathed. Hornfels (adjacent to the Poudrette pegmatite) Calcite Corundum - as embedded grey to blue hexagonal prisms Dolomite - as cream coloured rhombs with translucent greenish edges Epididymite - as off-white fibrous tufts and plates Fluorite - crystals as distroted tetrahexahedrons or cubes modified by tetrahexahedron faces, pale to dark purple in colour Gmelinite - as translucent to transparent plates forming swirling aggregates and rosettes Pyrite - as lustrous crystals exhibiting combinations of pyritohedron, octahedron and cube Quartz - as clear, smokey and pluym coloured prismatic crystals. Two specimens of doubly terminated crystals with a 3-phase inclusion were found Rutile - as blocky twins Monazite-(Ce) - as small, sharp, exceedingly lustrous, translucent to transparent orange crystals Strontianite - as translucent grey to colourless botyroidal aggregates Unknown in relict eudialyte - heavily striated clear plates sometimes forming Maltese crosses. Fluoresce white under both long and short wave, and do not appear to fuse at any temperature Marble Xenolith Apatite - as clear prismatic crystals in cavities in massive pectolite Analcime Apophylite Group mineral Calcite Carletonite Fluorite as clear to translucent, purple, green and zoned crystals exhibiting both simple and complex habits Grossular as transparent to translucent yellow dodecahedral crystals in association with calcite, an apophylite group mineral, and riebeckite Hibschite Mica Group mineral light brown hexagonal plates with a silvery sheen on broken surfaces Molybdenite Pectolite as fibrous and prismatic crystals and as fine to coarsely crystalline masses Pyrrhotite as brownish bronze hexagonal crystals in cavities in massive coarsely crystalline pectolite Tadzhikite-(Ce) as pale yellow micaceous rims on apophylite? in cavities in massive pectolite Titanite as transparent pink crystals on pectolite Vesuvianite Pegmatites Aegirine Analcime with aegirine inclusions creating rich glassy black plates of crystals Arfvedsonite Calcite Clevelandite Elpidite Eudialyte Fluorite as clear to translucent sea- green crystals in association with aegirine and sérandite Galena Genthelvite as aggregates of crystals coated with an unknown grey material in association with fibrous aegirine and rhodochrosite Lemoynite Family Molybdenite Natrolite Petersenite-(Ce) Quintinite-(3T) SEE "Notes From..." Rhodochrosite in many habits including simple rhombs, rosettes, sheaves, and rounded aggregates of platy crystals Sérandite as small, well formed, prismatic, translucent to transparent pink crystals Sodalite as embedded, blebby masses and as well formed, light to deep blue crystals in vugs Sphalerite as grey-green, opaque, rounded crystals with a pronounced greasy lustre, as sharp lustrous black to red-black crystal groups Zircon as transparent to translucent golden yellow crystals associated with sodalite and analcime MSH News - Malcolm Back The following three articles will published shortly, I have to verify a release condition on UK 96 = UK 106 = (new mineral species name) in press. Marc Favre UK 96 = UK 106 UK 110 = Tumchaite Niobokupletskite
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