 |
MSH News |
|
Table of Contents - Liz Fodi - Malcolm Back, Bob Gault and Bob Ramik - Malcolm Back - László Horváth - Tony Steede - Quintin Wight - Ronnie van Dommelen - Quintin Wight Mont Saint-Hilaire Confirmed Species, Nov. 15, 2001 - Malcolm Back, Bob Gault and Bob Ramik This list was edited by Malcolm Back, Bob Gault and Bob Ramik. Due to the size of this article, follow this link to find it in its entirety.  MSH News - Malcolm Back Micheelsenite (UK32) McDonald, A.M., Petersen, O.V., Gault, R.A., Johnsen, O., Niedermayr,G., Brandstätter, F., and Giester, G.(2001). Micheelsenite, (Ca,Y)3Al(PO3OH,CO3)(CO3)(OH)6 12H2O, a new mineral from Mont Saint-Hilaire, Quebec, Canada and the Nanna pegmatite, Narsaarsuup Qaava, South Greenland. Neues Jahrbuch für Mineralogie, Monatshehefte, 2001(8), 337-351. Adamsite-(Y) UK96 & UK106 Grice, J.D., Gault, R.A., Roberts, A.C., and Cooper, M.A.(2000). Adamsite-(Y), a new sodium-yttrium carbonate mineral species from Mont Saint-Hilaire, Quebec. Canadian Mineralogist. 38, 1457-1466. UK111 description (A. McDonald) This mineral occurs as gun-metal grey foliated groups, approximately 0.5 mm. across, in the interstice between aegirine and catapleiite crystals. It is also associated with calcite, siderite and annite. EDS has indicated Na, Ca, Ba, Mn and PO4. It was found last year (2000) in the "Poudrette pegmatite". Korobitsynite (R. Gault) Korobitsynite occurs in pegmatite with microcline, albite, calcite, siderite, rhodochrosite, catapleiite, rutile, aegirine, astrophyllite gp., fluorite. Korobitsynite and tsepinite-Na from Mont Saint-Hilaire - László Horváth The recent expansion of the eudialyte group from one member to 8 has already given us MSH collectors a fair amount of grief. We all recall that uncomplicated time in the not too distant past, when anything that looked like eudialyte was called eudialyte, and we knew what we had. No longer, as you all know, and the expansion of the group is not over yet. There is only a pause for a new nomenclature, and after that I am sure there is going to be more Russian-sounding mineral names to remember. If you think that the eudialyte group is getting complicated, you are in for a surprise when you see the details on the forthcoming nomenclature of the labuntsovite-nenadkevichite group. There are already 17 members in the group with a few more already in the works, and Dr. Igor Pekov, one of the principal researchers working on this group, expects the numbers eventually to exceed 25. Many of the new members have been approved by the IMA CMMN, but not published and the names are unmentionable at this time. The nomenclature will be published at the beginning of next year when I will attempt to review the group as it relates to MSH and St-Amable. However, with the recent publication of tsepinite-Na, it seemed like a good time to add this mineral and korobitsynite to the MSH species list and give a short description of them based on what we know. The tsepinite-Na was identified last year (even before its IMA approval) and the korobitsynite earlier this year by Dr. Pekov. Specimens of both species were collected a long time ago and resided in our collection as nenadkevichite. Many other MSH nenadkevichites and labuntsovites from different finds and associations were investigated by Dr. Pekov, most turned out to be correctly identified. It would not be surprising however, if some of the other members of this group turned up at MSH in the future, but the identification is becoming complicated, time consuming and expensive. Korobitsynite Na3(Ti,Nb)2[Si4O12](OH,O)2 · 3-4H2O Korobitsynite, an orthorhombic member of the labuntsovite-nenadkevichite group, was originally described from both Mount Alluaiv and Mount Karnasurt in the Lovozero alkaline complex, Kola Peninsula, Russia (Pekov et al., 1999). At Alluaiv korobitsynite occurs as colourless, prismatic crystals up to 2 cm long and at Karnasurt as anhedral grains up to 1 mm in diameter. Mont Saint-Hilaire, Vishnevye Gory massif, Ural Mountains, Russia and the Aris phonolite in Namibia are the other known localities.  The Mont Saint-Hilaire korobitsynite identified from the Horváth collection was found in cavities in igneous breccia on level 6 of the former Demix (now central-western part of the Poudrette) quarry in August 1976. It occurs as peculiar "wagon wheel" aggregates 2-3 mm in diameter, of colourless to pale gray, prisms. The SEM photo shown here first appeared in the Mineralogical Record (Horváth and Gault, 1990 page 326, fig. 97). Associated minerals included microcline, albite, aegirine, titanite, pyrrhotite, strontianite, molybdenite and zircon. Other specimens from the Canadian Museum of Nature and the Tarassoff collections have also been tentatively identified but may need IR data for confirmation. PEKOV, I.V., CHUKANOV, N.V., KHOMYAKOV, A.P., RASTSVATAEVA, R.K., KUCHERINENKO, Ya.V., and NEDELKO,V.V. (1999) Korobitsynite, Na3-x(Ti,Nb)2[Si4O12](OH,O)2 · 3-4H2O, a new mineral from the Lovozero massif. Kola Peninsula. Zapiski Vserossiyskogo Mineralogicheskogo Obshchestva, 128, (in Russian with English abstract); abstracted in Mandarino, (2001). MANDARINO, J.A. (2001) New minerals 1995-1999. Canadian Mineralogist, Special Publication, No.4, 131. Tsepinite-Na (Na,H3O,K,Sr,Ba)2(Ti,Nb)2[Si4O12](OH,O) · 3H2O
The MSH specimens (2) identified as tsepinite-Na in the Horváth collection was found around 1981-82 in a pegmatite dike in nepheline syenite. It occurs as vitreous, opaque, white, short prismatic crystals up to 4 mm long, associated with rhodochrosite, catapleiite, aegirine, sérandite and natrolite. SHLYUKOVA, Z.V., CHUKANOV, N.V., PEKOV, I.V., RASTVETAEVA, R.K., ORGANOVA, N.I., and ZADOV, A.E. (2001) Tsepinite-Na, (Na,H3O,K,Sr,Ba)2(Ti,Nb)2[Si4O12](OH,O) · 3H2O, a new labuntsovite group mineral. Zapiski Vserossiyskogo Mineralogicheskogo Obshchestva, 130, 43-50 (in Russian with English abstract). Another wonderful year collecting at Magic Mountain - Tony Steede Another collecting year over and more unknowns from Mont Saint-Hilaire. What could be better? It would be pretty boring if I could identify everything that I collected. I hope that readers will make suggestions with regard to some of the minerals that I have been unable to identify. I owe part of my success this year to László and Elsa Horváth. At the CMMA conference in May, the Horváths ably demonstrated the use of a spectroscope with microscopes. This piqued my interest and I have been using it extensively since. My thanks to the Horváths for introducing me to this very useful diagnostic tool. More on this later. Steve Szilard and I made the May trip, as always with great expectations. Our spirits might have dampened slightly as we spoke to other collectors before the gates opened and discovered that there had been little work done on interesting parts of the quarry. Still, I had been very fortunate in 2000 and was quite prepared to collect more of the same material. This included hornfels material from beside the Poudrette pegmatite and marble from the east wall. Well, imagine my surprise when I discovered that the hornfels beside the Poudrette pegmatite had been largely cleaned off since I had left it the previous October, leaving only intact wall rock, and the east wall had been moved back many feet and all signs of the marble had disappeared. As usual, the Poudrette pegmatite trench was full of people and I joined them, intending to try to split out some of the material in its west wall. In my way was a large slab of solid dark gray hornfels which I decided to try to move. This would have been impossible if it was not on a steep slope but I managed to flip it into the trench. Imagine my pleasure at seeing that much of the underside was banded with white (aplite ?) and it was vuggy. I happily broke up most of this material and carted it to the van. The vugs contained sprays of material that varied from white to translucent and almost silky light brown to charcoal gray. The lighter sprays looked identical to remondite-(Ce) that the Horváths had at the CMMA conference. Since remondite-(Ce) contains rare earth elements, I tested it for the spectral lines that the Horváth material demonstrated. Sure enough, I got nice spectral lines. However, I was able to have energy dispersion spectroscopy (EDS) done on one piece. Expecting it to confirm remondite-(Ce), I was surprised when sodium did not show up in the analysis. I still do not know what this material is, or even if all of the sprays are the same material. With the ‘remondite-(Ce)' are crystals of petersenite-(Ce), elpidite, adamsite-(Y), eudidymite, donnayite family, gmelinite, natrolite, and what I think are crystals of cordylite-(Ce). These are lustrous and dark brown. They show spectral lines but this is not much of a help because most of the donnayite and synchysite minerals provide such lines. There are also a very few white patches of very tiny lustrous crystals. They look prismatic and fluoresce blue-white short wave, nothing long wave. Any ideas? Igneous breccia, although for quite a few years that description would almost be considered an oxymoron. Nevertheless, I spied an interesting looking boulder at the north end of the quarry where some very large rocks had been deposited. I would have liked to work on it but Pete Richards was working on another boulder nearby and it would have been too dangerous. The next day Steve found a nice vuggy marble boulder. (He has a ‘thing' about marble xenolith material. I think he is still looking for the other half of a magnificent tundrite-(Ce) spray that he found several years ago.) We pulled out the heavy equipment and went to work. I don't think that I have seen any boulder of reasonable size resist Steve if he really wanted to break it. This one almost did. MSH marble is known for its toughness and this one contained just the right amount of pectolite to make it a real challenge. By the time the boulder had been reduced to garden rock size it was late in the afternoon and we had little energy left. I had left Steve for a while to spend a bit of time in the trench, where I was introduced to a collector carrying a Geiger counter. It turns out that the trench is somewhat radioactive. Fred Davis, of Connecticut, has done some excellent work on this and has narrowed the source down to the nice radiating sprays of elpidite. I have confirmed that all of the elpidite sprays that I have examined from this trench, even those attractive balls that came out three or four years ago, are quite radioactive. More work has to be done on this material. Happily, before leaving we went to look at the igneous breccia that I had seen the day before. It was almost time to leave the quarry but I was able to knock some pieces off and throw them in the van. Steve's marble had some spectacular pectolite, but that was not exactly what he was hoping to find. There was also some nice vesuvianite, apophyllite, a very little bit of hibschite, and some titanite. I was a bit more fortunate with the breccia. When I got it under the microscope, I found some very attractive clusters of gray to mauve bladed crystals radiating from a whitish interior (seen on broken clusters). The crystals are very small and the blades, when seen, look like short roman swords, sharp on all the edges. EDS on this material gives elements similar to those in titanite, plus a bit of niobium. Bill Henderson kindly did some optical work on these crystals and confirmed that they have very high indices of refraction which suggests that they probably are titanite. The same material contained yellowish clusters and balls that may be the same material but with even smaller blades. These are so small that I cannot distinguish the morphology of the individual crystals. It is likely that there are two types of these balls as some look very much like tadzhikite-(Ce) when split. More work is required on these minerals. Also in the tiny vugs in the breccia were some lovely stillwellite-(Ce) and steacyite. The steacyite shows quite a few different habits, including some with ‘wings' growing out of each of the prismatic faces, some balls with just the square ends of the steacyite terminations showing, and some very thin capillary crystals. This breccia material was so interesting that I wished that I had taken more of it. I didn't have to twist Steve's arm too much and we were back in front of the gate for the June trip. Most of my breccia boulder was still there and Steve and I proceeded to take it and one beside it apart. At one point Steve stopped to show me a lovely spray, almost a bow-tie, of prismatic crystals that were translucent, vitreous, and very pale brown. My immediate reaction was elpidite, as they looked very much like the sprays of flat terminated elpidite that had been coming out of the Poudrette pegmatite. I was very wrong. Fortunately, I also found a couple of these crystals. Still thinking that they were elpidite, which does exist in the vugs, I was surprised that they did not exhibit the characteristic bright green fluorescence of similar looking elpidite. Next, I tried the spectroscope. Bingo! I saw spectral lines, but not the ones that I was used to seeing. In almost every case, the spectral lines given by the REE bearing minerals from MSH are in the orange range, indicating neodymium, usually with at least one line in the green portion of the spectrum. This one had only a single line in the green, and nothing in the orange. I was seeing an erbium spectral line without the neodymium. As there are few minerals from MSH that contain erbium without neodymium, my list of potential candidates became very short. Indeed, to my knowledge there are only two minerals that qualify, and it wasn't horváthite-(Y). This left kainosite-(Y). I had never seen kainosite-(Y) and would probably never have considered it without the spectral test. However, it all started to fit; the right matrix, the right morphology, and the right shade of colour. I am indebted to Malcolm Back, at the R.O.M., for confirming the identification with x-ray diffraction and EDS analysis. There were a lot of other minerals in this breccia, including; yellowish catapleiite, titanite (the usual yellow crystals), tainiolite, leucosphenite, clear donnayite family, apophyllite that fluoresces green short wave (in ‘eyes' of bright green amphibole with feldspar crystals and a second amphibole), calcite that fluoresces red, lovely sphalerite of various shades, eudialyte family, apatite, pectolite sprays, galena, plates or lozenges that I am reasonably sure are ancylite-(Ce), and sprays of flat clear crystals, very thin and radiating mostly at 60 degrees, that I suspect are epididymite. Another unknown, found in the amphibole ‘eyes', are brown lustrous to waxy blobs that are almost covered by white crystals which may be natrolite. The blobs are very scarce and hard to spot because of the white crystal coating. There is no cleavage and the broken surface looks pebbly. These give very strong REE lines. Back in the trench, I found some more elpidite sprays, this time with my own Geiger counter. I could not see the elpidite but broke off a piece of the pegmatite that gave me a high radiation reading. Sure enough, it contained some nice sprays. We did not get back until the October trip. We went to look for more of the breccia, only to find that the quarry had changed again. Most of the boulders that had been moved to the north end were gone. We spent quite a bit of time looking at breccia boulders but even millimetre sized vugs were scarce. The Poudrette pegmatite trench had also changed. It had been swept clean in preparation for blasting and we were not allowed to collect in it. However, all of the material that had been in it was piled to the side and this represented pretty good collecting. Once again I got lucky by finding a very dark piece of hornfels that had some white streaks. Breaking it up I was rewarded with some vuggy material that looked completely black. The vugs are almost filled with a very dark amphibole, quite probably actinolite. With the ‘actinolite' are some yellow, doubly terminated, prismatic crystals. I cannot relate these to anything that I have seen at MSH. They show spectral line, so obviously contain rare earth elements, and they do not fuse, but turn gray in the blow-pipe flame. My guess is monazite-(Ce), but it is not a form that I have seen before. If it is monazite-(Ce), it would be the fifth type of which I am aware for the locality. The vugs also contained flat anatase crystals, gaidonnayite (frequently almost black with inclusions of the actinolite), medium brown crystals that are probably cordylite-(Ce), tiny donnayite group, and frosted blades that look like eudidymite but fluoresce bright green short wave. I assume that these are catapleiite. Breaking up the white banded material from this pile, sometimes referred to as ‘zebra rock' or aplite, resulted in nice yellow transparent donnayite family crystals, more elpidite sprays, ‘remondite-(Ce)', very nice gaidonnayite, corundum enclosed in the matrix, and what I think are brassy coloured flakes of nontronite. Breaking up the hornfels provided a few crystals that I think are bastnaesite-(Ce). These are not the usual balls of plates but are lustrous brown hexagonal crystals with pyramidal faces. They look a bit like single gmelinite crystals except that the flat termination may be very small or even not exist. They provide a neodymium spectral signature, and are identical to crystals that Cynthia Peat found and had identified as bastnaesite in 1994. Other minerals of interest in the hornfels are what I think are green monazite-(Ce) replacing another mineral, and some stacks of thin slices of hexagonal orange-brown, brittle, somewhat pearly, blades. With some difficulty I was able to see very faint REE lines. My guess is, again, cordylite-(Ce). Additional Comments I have recently had word from Dr. Andy McDonald regarding MSH specimens that he took with him from Brock. One is tiny, lustrous, sub-metallic black balls in hornfels, found last year beside the Poudrette pegmatite. These are rutile. The colour certainly fits but I would not have guessed rutile from the shape. The other is kind of hard to describe - quite small, light yellow or cream, slightly translucent, four sided prisms tapering to a point with steps (which allow the tapering) that reflect light when viewed at the correct angle. They areclustered in tiny vugs in a white matrix and they are quite difficult to orient. They fluoresce green short wave and red long wave. Zircon! MSH 2001 Initial Assessment - Quintin Wight "My acquaintance with Mont Saint-Hilaire was rather brief in 2001, for other commitments allowed me only two trips to the quarry. In fact, much of the material from both trips remains unexamined in the garage (the basement is full) because I have had so little time to look at it. Nonetheless, several interesting items did appear in the early sessions. On the May trip, I followed Marcelle Weber to a couple of small nepheline syenite boulders and asked what she had found. "UK 60," she said. That made me grab a few boulders locally myself and check them out. Sure enough, in the interstitial cavities were tiny balls made up of infinitely thin plates. There was one problem though. They were pink. UK 60 is described as being white. That being the case, I had them checked at the Canadian Museum of Nature. Sure enough, they were UK 60. It seems to be another case of things at Mont Saint-Hilaire assuming a different appearance from their original description. The May trip also gave me a single quintinite-3T crystal, tucked in with some aegirine from the area of the south corner pegmatite. The late July trip was less productive, although I say that without having checked it all. Still, I did come up with some unknown dark purple-red octahedra (not fluorite), some nicely terminated pseudomorphs of ancylite, perhaps after one of the burbankite group, and some pretty petersenite. Slightly more spectacular was a small miarolitic cavity containing dark green andradite garnets. I also picked up some fragments from a large boulder being worked on by one of our American friends, and discovered that it had some tiny, fragile, but very gemmy mangan-neptunite crystals mixed in with rhodochrosite. In short, in two trips, I found little in quantity, but some interesting variety, and a couple of rarities that were well worth having."
Created by M & H Systems |
Royal Ontario Museum