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Archive for the ‘Rocks & Gems’ Category

I just attended the Bancroft Gemboree 2015, Canada’s largest gem and mineral show. There are 3 distinct areas where rockhounds can explore their interest, the curling rink and the hockey arena which are both indoors and the outdoors trading stalls. In my experience the trading stalls are the best places to purchase minerals. Dealers come from all across the country, they have incredible    stories and the prices are phenomenal. Check out my youtube video on the Bancroft Gemboree here.

Barite from Morocco

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IMGP1430Well as you’ve probably gathered by the above picture, I’ve just discovered some pretty incredible mineral specimens – a pocket of gem quality tremolite at the contact between quartz and calcite veins. Tremolite evolves to actinolite under the right conditions, and sometimes changes to diopside. Anyway, the finer points of the discovery are detailed on my youtube site (caver461) and within the video details are provided for the purchase of my latest book on minerals – ‘Rockhound: An Experience of the North’. In the book I detail how to find gemstones and something of the experience of finding rocks and minerals in the north.

To see purchase details or for a preview, just type the book name into Google and click on the link, it will take you directly to the print company (Lulu), or click this link here for immediate access to the book on Lulu.

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Dragonfly at Feldspar Mine, originally uploaded by Mic2006.

This past week I was looking at an old feldspar mine near the former MacDonald Mine (Bancroft). It would appear that the whole area is pitted with abandoned diggings through the forest and the mineral varieties range from amazonite through to Ellsworthite and uranite, a deeply shadowed quartz (smoky) being indicative of the radioactivity that is inherent in several of the local mineral species. In fact in the 1950’s the Bancroft area was a major location for the mining of radioactives. This namelss mine that I visited in the bush was especially well endowed with the typical feldspar minerals.

As soon as I can get my Camtasia video editing software going you will be able to click here to see a short video on the trip.

Anyway this particular mine was along a barely distinguishable track that was lined with tailings which made great rockhounding possibilities. A word of caution, without even realizing it both Jeff and I cut our hands to pieces on glass sharp shards of quartz. Unlike feldspar which has a tendency to break cleanly and smoothly along natural cleavage plains, amorphous crystalline quartz breaks in a random, haphazard way with concoidal fractures – exactly like you would see in glass. You might recall that the Aztecs used to cut the chests of their sacrificial victims open with obsidian blades, this quartz is much the same.

Though bug season is now mostly behind us, they are still pretty bad in places, in particular around the stagnant water of the place that we visited. Perched on a rock in front of me was this giant dragonfly – I’ve never seen one quite as large as this. From end to end the dragonfly was probably about 4 inches in length and it sat dead still as I photographed it. You can see the circle of lights from the close-up function of my camera – reflected in its eyes. The best thing about dragon flies is that they eat blackflies.

Hopefully the dragon flies do their thing over this week as the Rockhound Gemboree 2013 is this coming weekend and those mineral gathering trips are always better when the bugs are fewer.

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Waterfall in cave, originally uploaded by Mic2006.

I suppose on of the most gratifying things about cave exploration is the ‘buzz’ that you get, and everything in existence seems to be encompassed in the yellow circle of your headlamp. Outside your headlamp there is mystery – turn your head and the mystery reveals itself. Each turn, corner and passage feels like it’s own first time discovery – I guess its something like the gambler’s buzz, and once you leave the cave the buzz dies away and then I feel like i’m in this slump and the rest of the week is grey and gloomy.

First human in a place that has lain untouched for several thousand years – beat that! How can you? The greater the challenge, the more the buzz. If somebody has already gone before you and poured a concrete sidewalk where’s the wonder there? I believe caving can become an addiction, and having caved for 26 years now I am hooked just like a junkie. And oddly I’ve become a connisour of rare and unusual sights – a flowstone dam, cave pearls, speleothems and speleogens, crawling in tunnels that are washed by frigid streams, deep tannin stained pools in marble, dolostone, calcite and limestone – privy to a sleeping porcupine’s bedside, wondering if a bear lies just beyond. Where does the waterfall come from? What wondrous crystal is that? some would pay a fortune at a mineral show, I prefer the mineral exactly where it sits – a concept of eco-mineral exploration which is something quite closely allied to ethical cave exploration.

See my latest cave trip here to the incredible beauty of Marvin’s Cave and its mysterious tunnels through marble beneath a forest escarpment.

I’d have a problem topping this discovery – Mountain River Cave here.

For more on caving see my book, ‘Caving in Ontario; Exploring buried Karst’ – there is a link on the right side of the blog that will take you to Lulu where the book can be purchased.

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JC and I have been privileged to recently explore an incredible secret cave whose walls are absolutely lined with crystals. (don’t ask where – we’ve been sworn to secrecy)

The cave leads down steeply from the forest in a rift of calcite that has been worn by running water. We initially entered from the upper entrance and worked our way downward beneath a low wall on a sloping floor. Everywhere there were crystals, they are most strongly concentrated in bands, but some of the larger crystals float in the calcite – beautifully formed with sharp and lustrous crystal faces. Some lie loose, having worn out from the calcite. There is a crevice into which I looked and within there was an apatite crystal about the size of a football just lying wedged there and from within that crevice there was a noticeable breeze that was cold and smelling of the earth.

JC and I proceeded up one of the waterways and found ourselves in this pothole pictured above.

see video on Julia Cave here.

Possibly one of the most exciting discoveries was what appeared to be a tiny jelly sack that was lying in the water and within the sack there was what appeared to be a filament like fishing line, about half an inch long but displaying every spectral color – all along its length there was a prismatic effect – like it was fire cast off from a diamond, and around that filament there wriggled tiny worms. So if one morning these worms burst from my forehead you know it was likely some alien species that i’d picked up in the cave (It would not be the first time).

So this recent visit puts us onto thinking about visiting more caves in calcite. Admittedly we are experts in finding limestone and dolostone caves, we have made some impressive discoveries over the years, but we know the clues in sedimentary geology/geography and it doesn’t take us long to root out a dolostone tunnel. Calcite is unpredictable, I can’t imagine that aerial photos will be all that useful, but we now have several leads and have visited two such caves (Both parts of Julia we count as one – there is also Milo Cave that I am yet to post on and the exciting discovery of an albino-ish crayfish which I photographed).

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IMGP3595, originally uploaded by Mic2006.

JC and I recently visited a cave in solid marble (The Natural Marble Bridge). Our intention had been to follow up river a short distance to see if there were other caves in the area. You might know the old adage – were there is some caves, there are more. Sadly there were no more that we found, but JC found a hole in another nearby valley that was blowing cold air and about 100 meters away, a hole (on the opposite side of the marble bridge) where it looks like the stream that presently runs through the cave must have sunk at one time. A cave dig might be in order when we run out of other going options.

The Natural Marble bridge has an entrance at one side of an elevated ridge of marble, and a downstream exit on the other side of the ridge. The entry way looks quite ominous and the roar of water is impressive – well out of proportion to the quantity that sinks.

Your passage through the cave is quite magical – traversing through bands of marble of various earthy colors, a granite contact being some short distance into the rock (facing downstream to your right).

See video of the natural Marble Bridge here.

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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.

The cavity is shown in my video – Click here for Crystal cavity in Bancroft video

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.

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Cave shaft – Canada, originally uploaded by Mic2006.

In the same area where we discovered the Tooth Tube, a cave that we have been clearing of a glacial plug of clay, we have also found numerous deep shafts, aligned along joints they tend to be deep and narrow with fluted sides and moss around their upper lips. To a caver, a cave shaft is generally indicative of something that might be occuring lower down. Often, but not always, the shaft represents the dominant passage of water as it drops beneath the surface, and as Marcus Buck had pointed out in the excavation of the ‘Birth Canal’ at Olmstead in the Eramosa Karst, “Usually if you follow where the water goes, it takes you on to tunnels”.

This particular field of shafts and pits is in an area that is not too far north of Toronto, Ontario , Canada. For a Torontonian I believe it is one of the coolest things to do near Toronto.

The shafts that we found occur in a plateau that sits well above a large body of water and though the local water table is sometimes known to be perched, it would appear that by looking down into some of these holes, it must still be way below the surface. Many of the more slender shafts appear to be relatively debris-free. Wider shafts tend to be clogged with soil and leaves and logs. They can approach a diameter of about 10 feet in width and we speculate that like in the St. Edmunds System, water may have entered the underground at a time when the area was beneath a kilometer thick sheet of ice. As the pressure head built up, the water beneath the glacier was forced down tiny crevices, down to the bedding plane, and then out at the base of the plateau. Most of these shafts are at the bottom of a conical depression of between 10 and 25 feet in depth. In an old manuscript Martin Davis mentions a stream that he had dye traced that seems to take most of the surface water from this area and drains it out at a single point in the cliffs around the edges of the plateau.

Strings of shafts line up along the general orientation of local joints and we intend to plumb the depths of one such shaft this weekend. Our best case scenario is to find an open cave tunnel that requires minimal digging to clear it. I dropped a bolder down one deep shaft where I could not see the bottom and after an impressive pause I heard the muted ‘thunk’ of tin that had been pounded by my falling missile.

In one relatively shallow shaft we have found a crevice that seems to drop down into a water worn passage beneath, that will be our first priority. It was hard to get a good look at the passage as the crevice above still requires some cleaning, but I had the distinct impression it was human sized and floored with cobbles like we found in the Wasteland Waterway – still to be pushed to its endpoint.

For a final look at where we got with our excavation on the Tooth Tube – Click for cave video of the Tooth Tube here.

Check out the shaft at C-H sink, it is also in an area where sinks dimple local fields. Check out a short video of the C – H sink here

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An unseasonably warm day – early March found JC and I visiting Southern Ontario on a search for abandoned gypsum mines.

Where both the Grand River and the Nith River meet there is the quaint though somewhat aged town of Paris. It has the appearance of having been passed by progress, there are brick and barn board sided buildings in the downtown – somewhat neglected, but full of character. Large mills had once tapped the water power and the mining of plaster of Paris leaves a fascinating terrain of forgotten rail embankments, inexplicable hollows and gullies along the river bank, weirs and beaches where barges once loaded up the chalky material from underground and of course decayed and vine choked foundations.

I was inspired to photograph this backstreet business, ‘The Grand River Experience’ it appears that they offer canoe and kayak rental as well as tours down the river; I believe it was on their website that I had my first glimpse of a riverside gypsum mine – supposedly one of many that are around there. As you might have guessed, there is a connection between ‘plaster of Paris’ and the coincidence of this calcium sulfate material being mined from a conglomerate that underlies the area. It is said that the gypsum comes from Silurian age lenticular deposits on the south east flank of the Algonquin Arch.

Devil’s Cave is one example of a local feature where running water has dissolved away the gypsum and having washed the conglomerate out, there are small cavities lived in by a colony of beavers and decorated by spectacular white speleothems and flowstone.

Having now visited this area several times and followed apparently sure leads, both JC and I are somewhat disillusioned as to the prospects of finding open gypsum adits – though a cave is far preferred. Everything seems blocked up real well (with the exception of a single adit along the river bank downriver from the town). Crossed shovel and pick symbols on a map (available on the internet) generally leads you to a spot where you’ll find an undercut that is pretty much buried in countless tons of soil.

Having long been fascinated by industrial archeology, urban exploration and various forgotten tunnel explorations I’d like to know of where there are old gypsum mines around Paris where an interested person can visit and actually go underground?

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There’s a crevice that cuts under a cliff face. It leads to an underground lake that just goes on and on. Dan and I spent about two hours underground wandering waist deep in water. I am thinking that the mine is somewhere between 100 and 170 years old.

Back in the 1820′s and 30′s there was a serious demand for building stone in Southern Ontario; Whirlpool Sandstone was one of the most valued materials. It was extracted from a  layer just above the Queenstone shale.

Near Belfountain you can see this rock at the base of Church’s Falls. See the chapter on Belfountain on page 69 of my book “Rockwatching; Adventures Above and Below Ontario” The rock that came from there was a maroon color and was used to build Queen’s Park and various buildings at University of Toronto. Down here in the more southerly areas of the escarpment the Whirlpool Sandstone seems a lot higher on the escarpment than it is further to the north. It is also more varied in color and I am told that it is possible to find azurite and malachite in chert pockets in that rock.

Anyway the construction of the Welland Canal generated a great deal of demand for building stone as did the increasing size of the urban structures around the “Golden Horseshoe.” Finally around 1900 the skyscraper came into being. The strength of the modern skyscraper comes not from its rigid outer shell but from its internal steel girder skeleton. This change in design meant that standard construction stones suddenly lost their market and materials such as Italian and Indian marbles started showing up. They formed a thin veneer as did materials like glass, labradorite and granite. they were in no way responsible for the buildings structural integrity. Sandstone had seen its day and the mines closed shortly thereafter.

Some years back year Jeff Mirza and I traveled up to Belfountain to see if we could find our way into one of these underground tunnel systems. Apparently there are several deep passages above the hairpin bend as you wind down from Belfountain into the Credit Valley. Jeff had even seen a picture of a shaft in the forest with a ladder leading down into the mines. After a day of trudging along the hillsides we came to the conclusion that the entrances had all been blasted shut. It was not the case here. The tunnels lie wide open. It was as much a historical exploration as it was a geological one. The rooms were quite low though generally very wide and initially lit by small shafts that cut up to a brambly plateau above. The vegetation was so thick that it was almost impossible to progress on the surface, nevertheless, the shafts of light on the underground lake were really picturesque.

At times high banks of rubble rose out of the water and it was necessary to slither along on our bellies. In places deeper into the mine calcite deposition had made a hard, translucent shell across the top of these banks and we had to be careful so as not to damage the profuse clusters of soda straws that were forming on the roof. The bats seemed quite perturbed by our arrival in their world and somebody was cheeping angrily from up a crack in the roof. On several occasions they fluttered by and I could just catch glimpses of their chaotic flight. I was surprised by the extent of speleothem formation in the mine. I had believed that under good conditions soda straws could grow at about an inch every hundred years though in remembrance of a winter excursion Jeff and I had done up a storm sewer in Hamilton a few years back, that one inch can be quite drastically stretched.

As we waded through the lake there were tunnels that branched off in every direction, the air  seemed dead and the steam that rose from our coveralls clung to us. it made photography quite difficult.

The water was so still and clear in one spot that I was surprised by the ripples when I crawled right into a pool. We continued on along a mound that was just beneath the surface. Dan wandered off to the side into the deeper water and suddenly found himself hip high in really treacherous mud. I had a similar experience moments later and we decided that further exploration would have to be done with an air matress. Up ahead it sounded like a heavy rainstorm and I think that there must have been a spot where the water was pouring in.

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