Eric
starting to shine!
if you build it and they dont come, your screwed
Member since January 2005
Posts: 31
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Post by Eric on Jan 25, 2005 14:44:05 GMT -5
hey everyone... has anyone tried to polish fossils??...i am on my first batch of rocks and i have a few fossils in it. i am on the 220 stage. i have one fossil that i am having some troubles with. it looks like a coral fossil, lots of small divits, almost like pores, the outside edge seems to be collapsing in two spots. my question is....how does this effect the tumbling??...will the outside continue to collaps??...or will the stage 2, 3 and final stage have little effect on it??...its in the tumble right now. just curious as to the out come. thnx in advance for any info!!!
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Post by connrock on Jan 25, 2005 19:41:26 GMT -5
Eric if you want the fossil I don't tink it's a good idea to tumble it.Silicon carbide grit will erode much harder material, such as quartz,quite fast so it will for sure erode your fossils. The 2 nd - prepolish stages will also take a lot of material off of fossils as they are usually very soft. Tom
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agatenut
starting to spend too much on rocks
Member since August 2004
Posts: 127
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Post by agatenut on Jan 26, 2005 7:09:46 GMT -5
Hey Eric First, what type of rock are the fossils on? If they're on limestone, forget about polishing. The rock's too soft. If it is on a silica based rock (it will not fizz in vinegar), you may be able to polish it. I've polished silica based fossils before. Some come out pretty good, but I've also wiped out some fossils that were light surface impressions. Be careful! ralph
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Post by connrock on Jan 26, 2005 10:53:19 GMT -5
Hi Ralph, Thanks for the info on fossils. I didn't know they could be polished. Thanks,,,,,, Tom
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Eric
starting to shine!
if you build it and they dont come, your screwed
Member since January 2005
Posts: 31
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Post by Eric on Jan 26, 2005 12:35:59 GMT -5
the fossil that i am refering to is not in a matrix...it looks like the end of a thumb (about that size). it literaly looks like a piece of coral. i will post a pic later on tonight. a few of the other fossils i have in there do have a matrix around them. its a silica based stone, not sure what kind or its mohs, it seems to be holding up rather well. other fossils that are in are small pieces of petoskie stone with a silt stone matrix. the silt stone is practicaly gone (which is good). one of thebest fossils i have in there, and its also the piece doing the best right now looks like a piece of poop. i mean just like a terd. but that one is polishing real nice. i am just concerned with the one piece. i think i will just wait and see what happens. if it looks like crap when i check it , i will pull it out. thnx for all the info folks!!!!
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stefan
Cave Dweller
Member since January 2005
Posts: 14,113
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Post by stefan on Jan 26, 2005 13:24:29 GMT -5
Eric- It is probably a fossilized piece of coral- It won't tumble and will continue to erode- Plus all those pores are a perfect hiding place for course grit- So cross contamination is very possible-- Hope it was not a valuable piece-
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Post by BearCreekLapidary on Jan 26, 2005 14:22:53 GMT -5
Hi Eric,
Welcome to the board!
I have tried to tumble Petoskey Stone without any luck at all. It's way to soft and the cross contamination is a major problem. Hope this helps some.
John
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Eric
starting to shine!
if you build it and they dont come, your screwed
Member since January 2005
Posts: 31
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Post by Eric on Jan 26, 2005 19:30:32 GMT -5
alright...couldnt find out how to upload the picture...but i think i will take the advise and pull it out...i just looked at the load and wow is the 220 grit small!! i can see how easy contamination would be!!....
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agatenut
starting to spend too much on rocks
Member since August 2004
Posts: 127
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Post by agatenut on Jan 28, 2005 7:18:41 GMT -5
I too tried to polish Petoskey stone and it disappeared on me! It really is way too soft to polish. In our local railroad tracks, though, I have found fossilized corral in silica based stuff and it polished really well. Found crinoid fossils too. I think some turritella fossils may be in silica matrix as well. ralph
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