Dundas Quarry, 40 km W of Hamilton, West Flamborough Twp., Wentworth County, Ontario
This is one of my favorite localities; I've collected here twice a year since the early eighties. The mineralogy is simple, but some superb things have been found over the decades, including very fine to world-class crystals of calcite, celestine, fluorite, galena, marcasite, and sphalerite.
Dundas is NOT a locality that you can visit any time you like! Access is limited to club trips, provided twice yearly by the Central Canadian Federation of Mineral Societies. Their page on the quarry, including maps, safety rules, and mineral photos, can be found here. Many thanks are due to Tim Elliot, quarry worker, who is key to our accessing the quarry. He has built a fantastic collection of Dundas minerals, and has kindly spent many an unpaid Sunday overseeing hundreds of collectors in the quarry, every spring and fall. He also provides large and superb displays of Dundas minerals to many local mineral shows, so if you run into him, say thanks and buy him a coffee.
Access of late (fall 2009) has been threatened by the idiotic actions of over-eager collectors, one of whom was spotted by a pit boss climbing a wall... a bit of a no-no. We were very lucky to even get in, in the spring of 09. LaFarge is a big company, and they gain nothing by letting us on their property. So if you go, follow the rules, and if you know who that wall-climbing clown was, punch his teeth out for me.
Many more photos to come, and hopefully we'll get some ID's confirmed too.
A view of the quarry from an upper ledge, spring 2007, gives some sense of scale.
Initial Mineralogy of the Dundas Quarry
Anglesite
Small but good brown micro crystals can rarely be found on or very close to weathered galena. The crystals vary from quite sharp to highly elongated and straw-like. Confirmed by EDS. To find this mineral, bring home all the galena you find, the more weathered the better, and examine it at 45x.
Superb crystals are found in a variety of habits, typically dogsteeth, occasional scalenohedrons, as singles or druses of xls, occasionally covering several square meters. Usually shades of yellow, to colorless. Enormous crystals have been found, to 35 cm long. Crystal clusters to 75 cm across and 225 kg in weight (!!!) were recovered by Tim Elliot from a large vug system, with the help of a pressure washer - the collecting process was preserved on tape. Rhombs are usually much smaller, excellent penetration twins have been found recently.
One of the more prized minerals from the quarry, typically thin to thick tabular xls to over 10 cm, and clusters, occasionally crystallized on both sides. Very fragile, requiring great care and, ideally, a diamond saw, to recover intact. Abundant as solid pods, completely filling vugs to 30 cm or more. Usually shades of pale blue, to white and rarely yellow, or purple from inclusions of micro fluorite specks. Tri-color crystals, white-blue-yellow, have been found. Terminations can be sharp to strangely feathery, white multiple- terminations on blue xls are common.
Cerussite
Greyish white powdery to finely xln coating on sulfides, as noted by Sabina, (GSC Misc. Report 39, 1986) Considering that anglesite xls aren't that uncommon, it's a surprise we don't see more and better cerussite. I'm not aware of anthing decent that's been analytically confirmed.
Chalcopyrite
Rare and, in my experience, of little interest. Noted by Sabina, (GSC Misc. Report 39, 1986), but I've never seen a really convincing chalcopyrite.
Dolomite
Presumably the minute rhombs lining all vugs are dolomite xls, but I've never seen a specimen of interest.
The king of the Dundas minerals! Locally abundant as sharp cubes, shades of yellow to brown, typically 1-2 cm, to a very rare maximum of perhaps 10 cm - the equal of any other Canadian fluorite for size and quality. Also colorless, or minute purple granular inclusions in celestine and calcite. Yellow-white fluorescence under SW UV. Some crystals have been found with ruler-like cuts, possibly caused by the fluorite growing around anhydrite crystals which have subsequently been lost to hydrothermal alteration. Fluorite seems fond of a certain color of rock; succesful collectors learn to spot the good boulders and take them apart. Diamond saws or a bit of luck are the only way to remove the larger crystals intact.
Common as silvery-grey smears, but uncommon as good crystals of any size. Cubes of 1 cm are good specimens, perhaps 3 cm is the maximum size. Superb specimens of cubes with modified edges were recovered from the famous sulfide vein, in the seventies, very large and fine pieces were etched out of calcite, without damage but also without luster. Nice micro octahedrons aren't too rare. Crystals of decent size must be carefully removed and trimmed, ideally with a diamond saw, as they are only too eager to pop off their matrix or cleave into multiple pieces. Micromounters in search of lead secondaries should keep an eye out for galena, weathered xls are often home to anglesite crystals.
Goethite
Noted by Sabina, (GSC Misc. Report 39, 1986) as rusty coatings on sulfides
Gunningite
Noted by Sabina, (GSC Misc. Report 39, 1986) as greyish-white coatings on sulfides
Gypsum
Abundant as white lumps filling voids, looking much like cauliflower. Worth examination as they're occasionally speared by celestine xls, or even possibly home to small but beautiful gypsum crystals, clear and colorless, beautiful with magnification. Glass-clear cleavage masses aren't terribly common but make nice specimens. Terminated gypsum crystals are quite rare and usually very small.
Halotrichite (?)
Not confirmed by analysis, but a pretty safe ID of the abundant micro white acicular material
found, with other interesting micro secondary sulfates, growing on decrepitating marcasite. These need work.
Hydrocarbon (AKA Bitumen)
Not a mineral but still sort of interesting examples of what time, heat and pressure can do to organic remains. Typically very light, shiny black material, very brittle, locked in matrix. Looks much like coal, or obsidian. Can also be soft to somewhat runny and tar-like, occasionally coating minerals like fluorite or sphalerite. The best specimens are lustrous balls or teardrops, or larger pure masses, to 4 cm or so.
Hydrozincite(?)
Unconfirmed weird xln micro white stuff on weathered sphalerite
Abundant as micro to small xls, found to some degree in almost boulder. The famous sulfide vein of the seventies produced large specimens. World-class material, hand sized matrices coated with brilliantly lustrous blades, has been found recently, though it appears that this was an isolated, one-time occurrence. Sadly the mineral is generally unstable, decrepitating into nasty acidic crumbs, and multiple micro sulfate secondaries, in a relatively short time. Hopefully the recent find will be neutralized by the limestone matrix and modern treatments, and survive, as they are truly superb specimens, as good as any marcasite found anywhere. Superb micro crystals are common, often beautifully twinned, and usually in association with pyrite. Commonly very closely associated with pyrite, the two of which are often confused by non-micromounters.
Pyrite
Common in small crystals, typically druses of tightly-packed octahedra, sometimes spectacularly iridescent and multi-colored. A couple of dozen habits have been found, incuding cubes, acicular needles, bizarre log cabin arrangments, etc. The best micro material was found in a rich sulfide vein in the floor of the quarry, up to about 30 cm thick, composed of vuggy marcasite, pyrite, and sphalerite. This stuff was unfortunately highly unstable, growing a nice fur coat of secondary sulfates, at least five different species, quite nice under the scope.
Pyrrhotite
Quite uncommon as thick to paper-thin hexagonal plates, singles or groups, seldom visible without magnification hence easily overlooked and mis-identified as rubbishy marcasite. The scope reveals that many are overgrown or pseudomorphed by another sulfide, presumably marcasite.
Quartz
Noted by Sabina, (GSC Misc. Report 39, 1986) as colorless to white crystals and botryoidal
aggregates. Very rare and relatively insignificant as specimens.
Rozenite
Colorless to white material, micro, weird, sort of ice-like, found on altered sulfides
Common in clusters and weirdly intergrown / twinned xls with curved faces that very rarely show more than a hint of the tetrahedral habit. "Individual" xls to 3 cm, clusters to perhaps 8 cm, typically brown to lustrous pure classic blackjack, or yellow, shades of orange. Lots of great specimens have been found, one could easily assemble ten or twenty thumbnails, all different. Also massive, granular chunks, with other sulfides, and rarely brownish botryoidal, from the sulfide vein exposed in the floor. Rare is the trip when at least one decent sphalerite doesn't turn up.
Strontianite
Currently seems very rare, but has been found in quantity in the past as small creamy white spheres, quite nifty specimens but hard to acquire now. Noted by Sabina, (GSC Misc. Report 39, 1986) as colorless crystals.
Sulfur
Noted by Sabina, (GSC Misc. Report 39, 1986) as yellow to rusty, coating sulfides. Said to have been found in small yellow crystals, but very, very rarely. I've never seen anything that looks like typical sulfur.
Fossils
Decent fossil specimens were more abundant in the past, when the more fossiliferous upper levels were being mined. Sabina, (GSC Misc. Report 39, 1986) mentions crinoids, corals, bryozoa, brachiopods, gastropods, and trilobites. I've found one large cephalopod. The dark, shaly rocks, highly bedded, are where to look for fossils and should reveal the odd brachiopod and trilobite fragment with enough examination. Definitely not a significant fossil locality at present.
Remember, this is just an initial writeup, more photos, info, and hopefully some analytical results will follow.
Have I missed anything, or can you provide specimen photos or collecting stories?
Suggestions and assistance will be warmly received! Contact me.