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Post by spiceman on Feb 21, 2016 23:28:13 GMT -5
Im a Ohio guy and flint is mostly my type of rock, very hard. ( a nice smooth result) but, I've recently found some that have imperfections. ( cracks lines, digs, rough areas...) Being such a hard rock should I ground the imperfections before I tumble? What is the standard procedure or is there one?
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Post by Toad on Feb 22, 2016 6:02:06 GMT -5
I'm too lazy for that - in general. Just throw it in the barrel. They keep tumbling until the imperfections are gone. This will leave you with a smaller stone in the end, but I'm all about less effort...
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jamesp
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Post by jamesp on Feb 22, 2016 8:21:30 GMT -5
Im a Ohio guy and flint is mostly my type of rock, very hard. ( a nice smooth result) but, I've recently found some that have imperfections. ( cracks lines, digs, rough areas...) Being such a hard rock should I ground the imperfections before I tumble? What is the standard procedure or is there one? With tumbling you really get what you put in there. Nice smooth rocks without divots cracks and imperfections sure do make the process quicker and end up with best results. Many schools of thought. You can grind them in the tumbler or pre-shape them or be selective before tumbling. If you have raw material in large amounts i suggest being selective and only tumbling the best shapes.
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Intheswamp
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Post by Intheswamp on Feb 22, 2016 8:50:24 GMT -5
I would be *very* suspicious of the "crack lines" that you mentioned. Fracture lines? My only experience is with fractures in quartzite and I don't know if fractures in flint are similar. But a fracture is a fracture, no matter what type of rock, I guess. In quartzite I believe fractures will basically always be there until the rock is almost ground away to nothing. In the clearer quartzite you can easily see where the fractures travel deep down into the rock. With opaque flint you can't see this, but I would think the fracture is still there. One thing, though, that is on flint's side is that the fracture will not be as evident as it will with the translucent quartzite...a fracture line on flint probably will show up as a thin line whereas a fracture line in quartzite shows an ungly whitish "crack" much like you would see in thick glass (old coke bottle, for instance). Look at this picture. It is a 15-20 pound load of quartzite that I tumbled for close to two months. My first big tumble. I had no idea (still don't reall!) what I was doing...I picked up a bunch of pretty rocks and I chunked them in the tumbler. I kept hoping that they would improve. I managed to get about 4 pounds of rocks out of the pile that I forwarded on to my Lot-O. The rest...I'm still debating on what to do with them. Unless I'm just experimenting or something, in the future I will be much more harsh in culling rocks going into the tumbler. Pits, divots, angles...those can be ground out if you want to grind them. Cracks/fractures...are usually more than skin deep. As jamesp alluded to, be selective in what you tumble. Garbage in, garbage out. Below is that picture I promised of what I had high hopes for. Note all the white lines/cracks/fractures...I really don't believe they will ever grind/tumble out. Here's the thread about them and what some people have suggested... What to do with these heavily fractured tumbled rocks....fracturedrocks (Custom) by Intheswamp, on Flickr
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jamesp
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Post by jamesp on Feb 22, 2016 9:04:12 GMT -5
The best material in the Alabama quartzite zone is inside the cobbles Ed. Note how the gravel bars are white. Because they are totally frosted and fractured on the skin of EVERY cobble. Open them and and behold the beauty within. It takes me a day and thousands of hammer wacks to fill a 20 pound barrel with quality quartzite, tremendous waste byproduct. I can hammer wack 20 pounds of fine coral tumbles in a half hour and have minimal waste and less fractured rock.
It is just the difference in the workability and accessible quality parts of the rock.
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Fossilman
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Post by Fossilman on Feb 22, 2016 9:59:21 GMT -5
I have Ohio Flint and it has healed fractures...I would grind the imperfections before tumbling (I always do anymore)..As said,it makes for a better tumbled rock and doesn't take as long to tumble...
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Intheswamp
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Post by Intheswamp on Feb 22, 2016 13:02:05 GMT -5
Fossilman, this is the second or third time I've seen "healed fractures" mentioned. I'm curious as to what this is and how it happens...any info? Thanks.
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Fossilman
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Post by Fossilman on Feb 22, 2016 13:15:07 GMT -5
My term of speaking about healed fractures-the fracture is seen in the rock,but it's solid,with no movement,where the fracture accrued. Thus nature,heat and (or) etc healed it back into the formation it was in with the rock.. Like a bone healing back to health.... A healed fracture can be worked like a solid rock,it's stable for most lapidary work.... Hope you understood that "Mumbo Jumbo" ...LOL Someone else probably could explain it better than I can....
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Shelbeeray
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Post by Shelbeeray on Feb 23, 2016 3:05:55 GMT -5
Ed, Generally, a "healed" fracture is one where a rock cracked and then a mineral mixture of some sort leaked in and filled the crack, thereby healing it. The rock still can break at that junction. It is more likely to be safely worked on a wheel or lap machine. Sometimes they make it through tumbles without opening up. It depends on what "filled" the crack. If it was something softer than the original stone, it may undercut. If it is harder than the original, the original may wear down more quickly and the "fracture" can end up sticking out.
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Intheswamp
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Post by Intheswamp on Feb 23, 2016 6:56:02 GMT -5
Thanks Fossilman and Shelbeeray. That's along the lines that I was thinking. Kinda of like a deep flesh cut turning into a scar...it will heal but the structure of the filled gap will be forever different from the surrounding area and may not be as strong...or maybe stronger (scar tissue). So a healed fracture is old as some rocks are?....does this mean that healed fractures normally show up in really old rocks? In other words, the rock was fractured but then it took another rock-forming length of time for more "rock" to fill the fracture? Not that any of this really matters but just some thoughts.
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jamesp
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Post by jamesp on Feb 23, 2016 7:12:53 GMT -5
Thanks Fossilman and Shelbeeray. That's along the lines that I was thinking. Kinda of like a deep flesh cut turning into a scar...it will heal but the structure of the filled gap will be forever different from the surrounding area and may not be as strong...or maybe stronger (scar tissue). So a healed fracture is old as some rocks are?....does this mean that healed fractures normally show up in really old rocks? In other words, the rock was fractured but then it took another rock-forming length of time for more "rock" to fill the fracture? Not that any of this really matters but just some thoughts. Here is an example of healed brecciated jasper Ed. The white(probably chalcedony) filled in the gaps between the red jasper fragments. Breccia is known for having seams filled in. Pet wood known for it.
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