 |
MSH News |
|
Table of Contents - Announcements - Karl Estes - Henry Barwood - László Horváth - László and Elsa Horváth - László Horváth - László and Elsa Horváth - Tony Steede - Tim Jokela Jr Collecting at Mont Saint-Hilaire in 1999 - László and Elsa Horváth The recent article in MICRONEWS by Tony Steede "Just how bad was the collecting at Mont Saint-Hilaire in 1999?" alluded to what collectors "generally conceded" as a rather bleak collecting year. Many collectors who drove long distances once or twice a year to MSH, were understandably disappointed with the material available at the field trips last year, especially when compared with collecting in the previous 3 - 4 years which may be considered as good to great years. To balance the impression of bleakness, we would like to offer a few observations and some specific details of our own collecting experience in 1999, and those of the local (Montréal area) collecting community. Reviewing our collecting log for 1999, we noted that we ended the year just under the 100 species mark, certainly not exceptional but not bad. It is interesting to note however, the reapparance in our log species we have not seen in recent years such as wöhlerite, tundrite-(Ce), leucosphenite, epidote, steacyite, vesuvianite (yellow tabular crystals) and the tadzhikite-like mineral, all of them in small very local concentrations. In the early summer, we have seen some excellent specimens of labunstsovite and catapleiite (up to 1.5 cm rosettes) being collected by several collectors, and in the fall Gilles Haineault found some very impressive smoky quartz crystals, intense blue carletonite (mostly massive) and some unidentified pseudomorphs. The Haineaults and other collectors including ourselves, have found superb specimens of UK 106 (the best speciemsns for the species to date with sprays up to 2.5 cm long), eudidymite (rich aggregates of sharp twinned tabular crystals up to 10 mm), horvathite-(Y) (some of the best with water clear crystal groups), elpidite (spherical groups of lustrous, greenish yellow, prismatic crystals), thomasclarkite-(Y) (rich specimens), leifite, (compact spherical aggregates up to 6 cm in diameter of opaque, white prismatic crystals) and gaidonnayite. We, as well as others have also found good specimens of gypsum, lepidocrocite (some included in gypsum), epididymite, neighborite, monazite-(Ce), monteregianite-(Y), narsarsukite (crystals up to 1.5cm), petersenite-(Ce), polylithionite, pyrochlore, rontgenite-(Ce), fluorapatite (the best and richest specimen in our collection), hilairite (pink), sodalite (var. hackmanite) crystals and a number of potentially interesting but as yet unidentified minerals. Of the new MSH species, in addition to UK 106, we have collected khomyakovite, oneillite and another new but unpublished eudialyte group mineral, as well as almandine (new for MSH, see note in this issue). Perhaps the most remarkable specimen we have collected is 5 x 4 x 3 cm in size that contains petersenite-(Ce), donnayite-(Y), gaidonnayite, UK 106, thomasclarkite-(Y), horvathite-(Y) and possibly calcioburbankite. Six or possibly 7 species for which MSH is type locality. In the final analysis, we have added many items to our collection some new species as well as some significant and "best-in-our-collection" specimens, and consider 1999, not only an interesting but a very satisfying collecting year. Many local collectors, including the Haineaults, concur that while it was not a "great vintage" year, it was a pretty good year.  Almandine from Mont Saint-Hilaire - László Horváth Almandine was recently identified by Bob Gault of the Canadian Museum of Nature by microprobe analysis (WDS) from a Horváth specimen collected in September 1999. The material was collected on level 8 in the central part of the quarry from a contact zone of sodalite syenite and hornfels. The contact rock hosting the almandine is best characterized as an igneous breccia which contained a very unusual light coloured rock with a texture strongly resembling granite, consisting mostly of white to salmon pink microcline quartz and a black mica group mineral. The unusual rock drew my attention and the spherical, red crystals embedded in it on superficial examination appeared to be a eudialyte group mineral which was sent to Bob for analysis. Unfortunately, the crystals which are up to 1cm in diameter are frozen in the microcline and no well-formed crystals were found. The colour is red and the crystals are invariably fractured, fragments are transparent and the lustre is vitreous. Associated minerals include microcline, quartz, pyrite, marcasite, fluorite, calcite, a black mica (annite?) and spherical aggregates of a yellowish beige acicular mineral. Although almandine is the most common member of the garnet group, it is very rare in alkaline rocks, and the only other occurrences reported from major alkaline complexes are from the Khibina massif and Vishnevye Gory both in Russia UK 110 - László and Elsa Horváth We have spent a lot of time during the past year searching unsuccessfully for UK 110, as did many other collectors. As far as we know nobody found this rather elusive mineral in 1999, and the known specimens (6-7) have all been collected in 1998 (during or after the July 25 field trip). UK 110 was found in cavities in the margin (in the banded contact) of the large Poudrette pegmatite dike on level 8, associated with smoky quartz, spherical aggregates of greenish-yellow elpidite (simple {110} prisms with {001} pinacoid terminations), gaidonnayite, siderite, and minor molybdenite and donnayite-(Y). It occurs as vitreous to adamantine, colourless (with a very pale pinkish hue), tabular crystals with a rhombic outline, forming fan-shaped groups up to 3mm across. The crystals are strikingly beautiful and unlike anything else we have seen at MSH, and once seen, visual recognition should be relatively easy. Galena alteration minerals from Mont Saint-Hilaire - Tony Steede In October 1996, I collected material which contained some altered galena. As several alteration products of galena are reported from Mont Saint-Hilaire, I decided to see if I could identify which ones I had. Given the small amount of altered galena available I am not certain of my identifications but whith the help of ultraviolet light, I am reasonably satisfied that I have anglesite, cerussite, and wulfenite, all from the same material. The material was abundant and came from below the biotite xenolith which was blasted out during the year. I believe that the material was available for most of that year. The matrix is mostly sharp crystals of aegirine in a massive (some of it blueish) natrolite. Some of the aegirine forms unusual balls and plates with flat terminations. Associated with the natrolite in tiny vugs are small nordstrandite clusters. To aid others who may have collected altered galena, the following are the descriptions of the various alteration product minerals. Most of these are from the Mineralogical Record, Vol 21, No. 4 (July-August 1990) written by László Horváth and Robert Gault with some additional comments from the J.A. Mandarino and V. Anderson book "Monteregian Treasures" as noted. Anglesite altered galena Cerussite altered galena yellow acicular wulfenite stronger pink-yellow long wave (Mandarino & Anderson) Hydrocerussite Wulfenite orange-yellow, dull tapering acicular crystals on galena pyramidal terminations In my material, the yellowish acicular crystals are diagnostic for wulfenite and the frequent association with cerussite is helpful in identifying the latter, as is the fluorescence. The resinous lustre of anglesite would appear to be helpful in distinguishing if from the hydrocerussite.
Created by M & H Systems |