Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,466
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Post by Sabre52 on Jul 19, 2010 17:59:45 GMT -5
Howdy folks, Cut a bunch of slabs today while working in the yard. Mostly stuff from our old ranch area back in California. Plus I cut some more toenails to sharpen my blade. Here are a few pics. Thanks for looking.....Mel The Devils Toenails. Some pink in this one: Firefly Jasper. Hard rock mined this from the exposed vein. Has some fractures but this is fairly colorful stuff. The darker areas are silicified hematite and usually polish out with a metallic sheen. Closer shot: Another hunk of Firefly. This piece has the wild pastel colors but no poppy development. This material is wildly variable. Some other examples I've mined are brecciated in purple tones and some just a myriad of tiny white dots on purple. Closer look: Sierra Jasper ( Hornitos Brecciated Jasper). This was thought to have been an extinct variety but I found one deposit on a neighboring ranch and my buddy actually found the old prospect pit from the 60's. This is the most colorful material which came from the old pit. This is a very odd jasper and some scientists say the breccia is actually broken up poppies. The dark areas are agate with specular hematite crystal and polish out as little sparkles. Closer look:
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zip
having dreams about rocks
Member since May 2009
Posts: 65
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Post by zip on Jul 19, 2010 19:01:46 GMT -5
Wonderful stuff! Thanks for sharing....I especially like the Hornitos......Zip
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Post by deb193redux on Jul 19, 2010 21:05:01 GMT -5
Sierra wins!
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Post by Toad on Jul 19, 2010 21:09:10 GMT -5
I like those. What makes a stone sharpemn your blade rather than dull it? Would softer rocks help sharpen?
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NDK
Cave Dweller
Member since January 2009
Posts: 9,440
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Post by NDK on Jul 19, 2010 21:35:04 GMT -5
Nice cuts Mel. The sierra is some fine looking jasper! I like the first firefly too.
Nate
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elementary
fully equipped rock polisher
Member since February 2006
Posts: 1,077
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Post by elementary on Jul 19, 2010 21:57:53 GMT -5
Dag nab it, Mel... You gone made me go out to that pile of your leftover poppy jaspers I have beside my house and pull out some pieces to polish. You'll see the results in a few days. By the way, is the Hunters Valley Jasper on this site from the same region as your finds? www.worldofjaspers.com/California2.htmlKeep on cutting! Lowell
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,466
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Post by Sabre52 on Jul 19, 2010 22:40:39 GMT -5
Toad: The dulling usually happens when the softer steel of the blade matrix gets pulled over the diamond or the diamond is simply worn down so little sticks up from the steel. I have used old silicon carbide 220 grit stones to sharpen my blades but I find softer stones like obsidian, fire brick, and this silicified limestone work well too. You just want something kind of abrasive so it removes the steel that often glazes over the diamond, to expose fresh diamond. The blade edges often get rounded too which on large blades is a giant problem and causes them to seize up in the cut. Hopefully the sharpening in that case cuts away some of the rounded blade edge to help it return to it's squared edge a bit but while I don't seem to have much problem with the ten inch blades, my old 20" constantly gave me fits.
Lowell: Yep. My old ranch was in Hunters Valley and the first example shown on that site is from one pit uphill from the Stinky Horse Hole while the second example is from a pit still further up the hill. The pit that first specimen came from is so worked out I only found a little tumble material remaining. The other site had quite a lot of material and my buddy and I barely scratched the surface. One of the best parts had nests of the fastest most vicious ants I've ever encountered. Hit the nest while digging and they got in my pants before I knew it and about ate me alive! I've dug both those and maybe an additional ten or so more sites to boot just in that one area and the area of jasper outcrops is huge......Mel
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Post by deb193redux on Jul 20, 2010 8:38:49 GMT -5
Toad has a good question that I have been thinking about. Why doe obsidian, which is softer than agate/jasper AND SiC (which is harder) both work to condition the blade? IF the two ends of the spectrum work, why not the middle?
I do not have the full answer. I think each does a different type of conditioning. One works best for exposing more diamond by wearing down the steel surrounding them, and the other (obsidian I think) works best for removing thing metal coating that has glazed over the diamond.
But, I don't think it is as simple as that. On the other hand, cutting a bit of fire brick helps, and I am glad to know the trick.
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Post by Tonyterner on Jul 20, 2010 8:40:09 GMT -5
Some really cool slabs. The Sierra is certainly the nicest. Thanks for all the info as well.
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,466
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Post by Sabre52 on Jul 20, 2010 9:12:44 GMT -5
Yeah, regarding the blade sharpening thing. I think it's more the texture of the material you use for sharpening rather than the hardness. If you think about it, materials like jade, rhodonite and hard agate are the worse things to dull your blade and they're all tough and either fibrous or microcrystalline, even when fairly soft relative to steel. They tend to drag metal over the diamond or just flat wear the diamond down. Both the harder and softer stones we use for blade dressing tend to be granular and either cut or sand the metal away from the diamond creating a fresh cutting edge.....Mel
PS: I have no freaking idea why obsidian works. I find it hard to believe it has much abrasive action but it obvious does so it must create some kind of granular interface or cut the steel as the blade grinds it away.
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