mp166
starting to shine!
Member since March 2011
Posts: 30
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Post by mp166 on Apr 11, 2011 7:51:41 GMT -5
Hi folks
We were out the weekend collecting fossils, and the area we were searching had lots of pyrite fossils, as well as lumps of pyrite just laying around, all of it is black colour, it got me thinking (always a bad thing lol), can this be tumbled, I looked it up in the field guide and it's 6.5 mohs so hardness not a problem, would I end up with shiny gold coloured material or just shiny black lumps. Anybody else's experiences much appreciated.
MP
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flkate
starting to shine!
Member since March 2011
Posts: 43
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Post by flkate on Apr 11, 2011 9:49:45 GMT -5
I remember seeing a thread in the photo section in which someone had tumbled pyrite. If I see the thread again I'll attach a link, otherwise you might can find it with the search function.
Post pictures if you do it, I LOOOVE pyrite! Kate
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stefan
Cave Dweller
Member since January 2005
Posts: 14,095
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Post by stefan on Apr 11, 2011 10:02:19 GMT -5
Can be tumbled. If I remember the thread, it was very messy, and fractures along cleavage planes. I Also believe it will stain other rocks so you want to run it alone. THe black "should" wear away (surface oxidation), but you may find that the entire chunk just crumbles away.
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mp166
starting to shine!
Member since March 2011
Posts: 30
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Post by mp166 on Apr 11, 2011 10:46:21 GMT -5
Thanks for the info
I'll pick up a bag full next time down there, all i've got to lose is a little time and some 80 grit.
If i strke gold i'll post some pics lol.
MP
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Post by gr on Apr 11, 2011 12:10:45 GMT -5
Do yourself a favor and don't just pick up every piece you see. I don't know how much tumbling you have done, so I'm assuming here, be selective; as you think, would this dissapoint me when I open up the barrel.
gr
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mp166
starting to shine!
Member since March 2011
Posts: 30
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Post by mp166 on Apr 11, 2011 12:21:26 GMT -5
Thanks GR point taken, i'm fairly new to tumbling so all advice appreciated.
MP
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racevw112
starting to spend too much on rocks
Member since August 2010
Posts: 174
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Post by racevw112 on Apr 11, 2011 12:46:49 GMT -5
I thought about tumbling some, but have not done it yet. I had a chunk I cut in half and polished, the flat side, by hand. The sanding turned the water black almost instantly, even though it was shining up. I want to say some others side it gets the barrel real stinky. May try it someday when I have an extra barrel and nothing to lose.
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playin4funami
noticing nice landscape pebbles
Member since March 2011
Posts: 87
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Post by playin4funami on Apr 11, 2011 13:11:37 GMT -5
might ry picking up a bunch and tumbling it nice and clean with just soap and water for 24 hours, then pick out the best looking chunks to try to polish, chunks without much for fratures and negative stuff that looks like it will fall apart, might even consider some cushioning media even in the rough stage to help gaurd against breakage, sounds like fun,love experimenting with things, just don't get any expectations up and be prepared to end up tossing out a whole batch,lol.
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chromenut
fully equipped rock polisher
Member since December 2009
Posts: 1,971
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Post by chromenut on Apr 11, 2011 16:04:30 GMT -5
I was not ready for my first piece and had just started experimenting with my flat lap at the time. Bad timing, got black stuff all over me! lol... but it did shine up beautifully, took a bit longer than normal and very careful work, but I like the end item!
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mp166
starting to shine!
Member since March 2011
Posts: 30
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Post by mp166 on Apr 22, 2011 10:04:53 GMT -5
As a follow up, somebody who has tried it advised not worth the mess, i also hand polished one fossil to bright silver, next day almost black again, tarnish that quick, i'll stick to agate.
MP
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stefan
Cave Dweller
Member since January 2005
Posts: 14,095
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Post by stefan on Apr 24, 2011 8:23:43 GMT -5
The tarnish may be caused by a bacteria. After polishing try spraying with bactine. It sounds crazy but 20 years ago there was a ton of pyrite on flourite coming outta china. The flourite would turn black and crumble away within a couple months. The dealers discovered that a bacteria was causing this and started to spray them with bactine that stopped the process
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racevw112
starting to spend too much on rocks
Member since August 2010
Posts: 174
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Post by racevw112 on Apr 24, 2011 18:54:10 GMT -5
Very interesting on the bactine, could not hurt. There are some fossils that are found in Waco, Texas that have lots of pyrite in them and folks talk about pyrite "rot" and the fossils will dimish away over time.
I sanded some pyrite by hand several months ago and it's still has not tarnished back yet. But it may be a different type of pyrite that I have.
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