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Posts Tagged ‘collecting minerals near Bancroft’

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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Beneath Robillard Mountain

Craigmont is about as distant from the reach of the modern world as you are likely to get in the “near north”. Indeed it appears on the map as a substantial settlement but as you cruise up Boulter road you become aware of how far you really are, both geographically and culturally from the bustle of Southern Ontario.

Coasting over hills that stretch off greenish-blue into the summer haze it seems as though you are crossing into a time warp. Meadows are saturated with intense colour and high pastoral fields line the road, strewn with orange and yellow flowers. Beyond this lies the valley of the “Little Mississippi River”. Spike-topped conifers wander unbroken to the horizon and in hillside fields lazy cows watch disinterestedly at the crumbling demise of old log barns.

As a collecting locale, Craigmont is remarkable. Not only is the beauty unsurpassed but its minerals are spectacular. Corundum here is found in large euhedral (perfectly formed) specimens; lapidaries have been known to cut them into cabochons. In their book, “Rocks and Minerals of Ontario” the Ontario Department of Mines say that there are unusual curved mica crystals. Garnets, molybdenite, allanite, uranite, euxenite, magnetite, pyrite and hornblende also appear from time to time.

Blink and you just might glide past Craigmont. The inhabited part is now a private town. It exists as a cluster of houses, barns and sheds and around it the vegetables flourish in earthy rows.

Robillard Mountain is situated within sight of the present habitation; an impressive upheaval of rugged red rock. Some twenty separate excavations scar its slopes.

As a general rule most corundum is found in pegmatites and structures associated with nepheline syenites. In this area north of Bancroft the most abundant deposits (corundum) are said to be sandwiched between scapolite, nepheline andesine and a band of alkaline syenite.

I took a hike beneath the mountain to see the syenite from below.

More on corundum in Craigmont here …

Check out this abandoned mine in Cobalt ... Here

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