The photo this week is of another self collected beauty. I collected this piece below at the Marmoraton Iron Mine in Marmora, Ontario a few years ago. When I found it none of the garnet crystals you see were visible. They were all covered by a thick layer of calcite. I could just make out the edge of a broken crystal at the side. However, I have been collecting at Marmora a lot and I knew that this had the possibility to turn out beautifully since at this quarry calcite often hides terrific and undamaged crystals below. You can still make out a little bit of it here and there (it is yellowish white). The key is to just get rid of it. Luckily, for me and many other collectors of Marmora minerals calcite dissolves easily in hydrochloric acid. So cleaning a find like this becomes a simple matter of placing it in a basin of HCl and waiting for the magic (chemistry) to happen. After a few days, and a few changes of the acid the result is what you see pictured below: a beautiful cluster of 1-1.5cm grossular garnet crystals, with some magnetite veins, minor epidote and left over calcite.
(Photo: Matt Herod)
Unfortunately, the garnet crystals of Marmora are not gem quality or anywhere near it, but they do form very attractive crystals of which I have a large, large number after years of collecting there. Marmora is also a great place to collect epidote, pyrite, calcite, pyrolusite, magentite, ilmenite, marcasite and actinolite. All of which are common and relatively easy to find with a bit of work. e.g. sledgehammering.
The quarry is larger than the town of Marmora!
Cheers,
Matt
p.s. Watch this space for EGU2013 updates starting tomorrow!! I’m really looking forward to the Fukushima press conference.
