In the Fall 1998 edition of the Canadian Caver, Brad Wilson relates an interesting experience that he had while exploring a remote cave in the Canadian Shield. He says that he could see a small room beyond a horribly tight squeeze so instead of going face forwards like he would normally do, he went feet first and after a little struggling he suddenly slipped through into a tube – chest deep into icy water. As Brad points out, to have gone head first would likely have been the end of him.
Exploring the rock from within, as we did at Twin Trickles Cave was certainly an amazing experience. The marble and calcite was incredibly sculpted and at the bottom of the shaft pictured above, there was a room that was bowl-like, and entirely striped black and white by the surrounding rock. When I mention a cave in the same sentence that I mention Bancroft, I do not for an instant suggest that it is a site for rock and mineral collecting. Caves are natural wonders that have been thousands of years in the making. They should be left exactly as they are found.
Twin Trickles Cave is some short distance into the forest and on the day that we visited, it was horribly inundated with ferocious black flies – food for the bats that reside within. although Twin Trickles is not a large cave, the rooms are sizeable for Ontario and there is a long tubular tunnel that seems not to have been followed either by ourselves or Brad’s group in 1987 – obviously it is no easy task and it dips down toward the water table. There are plenty of unprobed leads in the area of Twin Trickles so there will be more trips up in that direction this coming summer.
I am by no means a professional rockhound. My education is as both a gemologist and a geographer, but I believe both rockhounding (collecting minerals) and my other great interest – caving have been in my heart since childhood. And where better to rockhound than Bancroft, but a word of caution, as both rockhounding and caving appear on my site. Both activities are related to rock, but neither should ever meet. Cave mineral deposits must stay in the caves and a caver who shares both interests (and there are many) should never let their inner rockhound loose beneath the surface.
Wearing my rockhound persona this past Saturday afternoon I headed out to the Bancroft Chamber of comerce to get a vibe on the local collecting possibilities. For a place that styles itself as the mineral capital of Canada, they do very little to encourage that reputation. Remembering back to my childhood, rockhounding was everything in Bancroft – now it is just faded memories and hanging onto loose and fragile threads. Fortunately mother nature takes care of basics and continues giving back. I left the Chamber of commerce disillusioned – not by the staff, not their fault, just the general malaise of the people who call the shots. No effort to justify the reputation.
Anyway I picked up an ice Cap from Tim Hortons and headed off on a kind of aimless ramble, and within about half an hour I’d come upon a spectacular crystal vug (cavity) from which I spent the next few hours scooping crystals.
It was a calcite seam within a road cutting that had been opened by someone else and then abandoned as they obviously did not know what they had found and if they had looked within the cavity when they hammered it open it would be they not me who was posting the pictures.
My point is, you just need to know what to look for. Bancroft is famous for its calcite intrusions, a mineral that solidifies last from molten rock and so it acts as a medium for other minerals to grow in. The vug that I extracted crystals from was predominantly filled with amphibole and feldspar crystals and lying loose in the bottom of the part of the cavity that I dug into were a few doubly terminated crystals – having grown in the medium as opposed to being attached to the cavity wall. In retrospect, looking at the video it becomes obvious that the seam runs on an angle and there is likely to be a lot more to be extracted if rockhounds just follow up and down along the incline of the seam. As this rock cut is in a public place I will just leave its exact location for you to figure out, but there is enough in what I have said and shown on the video for you to quickly pin-point the general vicinity of the deposit.
I paid my $2 at the house of the landowner whose property I had to cross and then headed off into the woods. I’d heard that the path to the mine was about 4 miles long (it was not), but possibly longer, and the route was signposted (it was not- or should I say, it was in places).
The attraction at the Silver Crater Mine is a pit and adit that are rich in Betafite crystals. I found a lump of calcite with the top of one such crystal sticking out. It looks like the dull grey top of an octahedron. The adit burrows through a granular calcite which in my opinion does not make for a well-supported roof. So my advice about the adit is to stay out. I went in about 10 feet before coming to this decision.
Aside from radioactive betafite, there is also apatite (turned red by radiation), large books of biotite and horneblende.
I picked up some beautiful red Rubellite tourmaline at the 2011 Bancroft Gemboree yesterday. This fellow had 2 grades, the lesser grade he was selling at $40/carat and by weight the specimen that I picked out amounted to $64. Admittedly the color was not quite on a par with the higher grade, but there was less in the way of inclusion and the cut was of good symetry and deep so no light was spilling out a window.
I initially decided to go hardball and said that if he wanted to go $40 for the specimen it was sold, but he did not so I went away for a few hours, thought about it and came back and gave him his price. I suppose the value was what I was willing to pay for it and I really love red tourmaline.
You can see the gem that I bought on the tray to the left of the picture.
All in all, some of my favorite vendors were missing from this year’s venue – in particular Alpine gems and a couple of the cut stone dealers that I have so enjoyed in the past, also the better gem vendors seemed more evenly distributed between the upper and lower venues with what seemed a bigger focus on fossils than in the past. I was pleased to see the CGA presence and I had a discussion with my former tutor who advised me that the likelyhood of finding a natural alexanderite of the size that I mention was very slim indeed (with reference to a specimen that I had recently viewed but was unable to clearly see inside because I was in a rush and was yet to clean it).
One of the more exciting events of my rock-related year is the Bancroft Gemboree where i can schmoose with other rock-focused people. You absolutely know that this weekend the accommodation in Bancroft and for miles around will be booked solid so either I will be staying with my sister or possibly in Peterborough.
At the Bancroft Gemboree there is every natural crystal from the beautiful to bizarre – a booth of Columbian emeralds, Pakistani Peridot dealers and Russian fellow who sells black power pyramids of some unnamed substance. You stand there long enough he’ll have you convinced to put one in your living room – an investment that will turn your life around. Well if you believe that crystals will heal your warts, you’re well advised to see him as you’re likely thinking along similar lines. I’ll get a picture if he’s there this year and see what he has to say.
If you are into crafting, beading, crystals or geology, or just looking for gems, rough or cut, the Bancroft Gemboree is an event that goes beyond the material presentation of those goods, it’s a cultural event that bonds a motley crowd of locals to a throng of rockhound and crafting visitors. There are two huge venues, though I have always found that the better gem-stuff is in the venue lower down the hill. The best deals at the gemboree are typically outside at the top of the hill though last year I was disappointed.
Maybe next year I’ll get a booth and flog my upcoming Ontario cave book there.
At first glance the Essonville Road Cut looked much like many others in the area – gnawed upon by rockhounds and strewn with shards of calcite and sand. Most immediately obvious were the huge black crystals that protruded from the calcite – a dyke that is theorized to run off into a southerly direction onto private property. A sign on the fence behind the cutting advertises “Rockhound Eco-tours”. A rockhound eco-tour? It almost seemed contradictory.
“You’re a rockhound?” I asked the fellow crossing the road from the pickup he had parked on the opposite shoulder – “You might say that”, I was told with a grin. “I am more a prospector and I operate the eco-tours – like to show the minerals on my property but we prefer not to set pick or hammer to them. We like to think of ourselves more as stewards”. “Stewards?” “Yeah, caring for the land. I know it sounds hokey, but I think we were meant to have our property – to look after it. Collecting can be destructive”.
I kind of edge my rock hammer around behind me. “Is there a problem with us collecting here I ask? Nah, its public land. Place is already trashed with all the blasting”.
In reverent terms Mark explained, what had formed in the cutting was Fluor-richterite. You will notice that some of the crystals have a metallic sheen – kind of stained by an iridescence, Its only a skin of goethite, beneath it is still fluor-richterite, one of the few minerals that can really be called “totally Canadian”. It was only distinguished from hornblende and recognized as a separate species in 1976”.
“So, in truth, you would have a hard time distinguishing between the two?” “Not really” my eco-teacher told me. “They are both amphiboles and they form a solid solution series, but fluor-richterite has a scaly white surface and it forms in prisms that are longer and thinner than those of hornblende”.
“Do you sell any specimens?” I ask hopefully. “How can you put a dollar value on them?” I am chastised.
As fortune would have it, I found myself in the company of Lee Clark later that afternoon. Having seen the township’s blasting Lee had asked for the debris to be dumped beside his barn; he had scooped the lion’s share – enormous boulders with fluor-richterite spines and as Lee pointed out hexagonally appearing prisms that cleave away in flakes. “phlogopite mica; they used it for windows in the old wood stoves.
Having weathered out of the calcite there were doubly terminated prisms lying amongst shards and unusually shaped prisms that appeared fully formed on the one edge and flattened on the other. I was in the process of trying to decide what unusual growth condition had so stunted the crystals when Lee apparently read my thoughts “The prisms frequently cleave down their center,” he slipped me a smaller perfectly formed specimen that he had been carrying in his pocket. “It’s my worry stone” he explained, “You take it; folks down south have greater use for that than I”.
If I was asked to pick one gem as my favorite, it would definitely be tourmaline. Look at these colors. These cabs are in a tray that was displayed by a merchant at the Bancroft Gemboree.
Red tourmalines are known as “rubellite”, one of the better known deposits being some 30 kilometers south east of Mogok in Burma where the gem is found in an alluvial bed of decomposing gneiss. Chinese miners generally worked this deposit as red tourmaline was needed for the buttons of mandarin’s gowns.
This is what ruby and sapphire looks like in their rougher forms. They are hexagonal crystals, generally displaying a six sided shape and in the case of the cabbed ruby in the fore-ground, also showing some pretty obvious hexagonal zoning. Zoning indicates the placement of the rough crystal faces as the crystal grows. There is a continuum between corundum and sapphire, both are of the chemical formula aluminum oxide, its just the quality of the crystal that dictates whether it will be a gem or a mineral specimen.
I found the blackish crystal encased in calcite at the Faraday Hill road cut near Bancroft; only the tip was protruding from the rock and I roughly chipped it out and dissolved the calcite from it using Coca Cola.
The two rough reddish crystals are Mysore Rubies from India – not woth much at all and the cab is also from India, I bought it from Sahib for a couple of dollars – its way to opaque to be of much value but I liked the way it showed the zoning so clearly.
If you want it you can find it at the Bancroft Gemboree.
Yeah – they look like fletched arrow spines, barbs on fish hooks or just poorly made hooks but as the vendor explained, they are naturally occuring pieces of silver wire.
I am especially interested in what can be found up in cobalt. There was a massive silver strike up there in the early 1900s. According to the fellow that I was speaking to he said he had no luck in Cobalt – shook his head like it had been a really distasteful experience. “Got these from California”. I suspect he was keeping me clear of a rich hunting ground.
These pieces of silver wire are sometimes found in tangled balls and at other times in thick strands like the branches of a dead tree.
This lady was selling pink buddhas at the Bancroft Gemboree. I have just got back from spending the weekend there and I have taken a number of interesting photos of the people and the minerals that were being sold. This was the first person that I saw as I walked in.
Following the release some time ago of my book "Rockwatching; Adventures above and below Ontario", I am pleased to announce the release of my new book "Tamarindo; Crooked Times in Costa Rica". It is a story of opportunity. Edgehill Press is the publisher. (www.edgehillpress.com)
Cave Shaft at Twin Trickles – exploring rocks and minerals from within (Bancroft), originally uploaded by Mic2006.
