rockhound97058
freely admits to licking rocks
Thundereggs - Oregons Official State Rock!
Member since January 2006
Posts: 760
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Post by rockhound97058 on Jan 15, 2011 0:00:52 GMT -5
I recently posted this as a add-on to a different thread. Many people commented on it and a few sent me notes via PM about the post. I felt I should hi-lite it on a new thread for others to find and enjoy. When cutting sheen type obsidians such as Rainbow, Gold, Silver Sheen - Most pieces contain flow bands which looks like a stack of lines or parallel banding on the exterior of the stone. This is what you should see on the exterior of the sheen type glass, especially Rainbow. Each one of those lines is a different layer of color or sheen When cutting Gold and Silver sheen I like to like up my saw blade perfectly in line with a single band. This usually produces a solid slab of color. Rainbow I do basically the same thing, but just before I start the saw I bump the piece so I cut at a slight angle. By doing this your slab should produce several colors. You can line it up perfect with each band and produce one color per slab which might work better for cabbing - Once you grind a cab you'll pass through a few bands of color giving your cab a bullseye. This is lined up in the saw to make a proper cut This is after I make a cut showing the rainbow pattern. This specific piece had some silver sheen and green sheen in it. If cutting spheres from Rainbow or sheen type Obsidians - regardless which way you line up and cut, about 95% of the time you'll produce a sphere with a bullseye pattern. The only time I've changed the pattern is cutting pieces which have been twisted and squeezed during formation and have crazy flow banding lines on the exterior.
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Post by roy on Jan 15, 2011 0:28:07 GMT -5
thanks again jason ! what do you do ifyou have one with the crazy flow? roy
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rockhound97058
freely admits to licking rocks
Thundereggs - Oregons Official State Rock!
Member since January 2006
Posts: 760
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Post by rockhound97058 on Jan 15, 2011 2:19:11 GMT -5
If I encounter a piece with zig zag type flow bands, I still orientate the blade on one straight line and I pick a happy medium and cut through it. You'll still produce sheen pattern, but it'll be a wild looking color and pattern. It's actually pretty common to find pieces with various shaped lines. Dang Mother Nature had to give us some challenge ;D
Another trick I've heard over the years for guys who have a hard time finding the pattern. if you break a piece of rainbow where you see the color. Find the brightest color and keep your eyes focused on it. Then dip the bottom edge into a paint can. This will yield a proper cut line marked in paint to follow with your blade. That's a bit unclear without pictures, but hope folks get the idea.
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Post by gr on Jan 15, 2011 10:38:58 GMT -5
Jason, I'm going to send a pic in a pm latter for some advise if that's ok ?
Gary
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rockhound97058
freely admits to licking rocks
Thundereggs - Oregons Official State Rock!
Member since January 2006
Posts: 760
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Post by rockhound97058 on Jan 15, 2011 12:31:18 GMT -5
Not a problem. Happy to help out!
Jason
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Post by johnjsgems on Jan 16, 2011 9:51:08 GMT -5
Jason, I've never worked with obsidian but always wondered how the Mexican vendors get the rainbow obsidian hearts so perfect. Now I get it. Thanks for "spainin".
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rockhound97058
freely admits to licking rocks
Thundereggs - Oregons Official State Rock!
Member since January 2006
Posts: 760
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Post by rockhound97058 on Jan 16, 2011 11:57:55 GMT -5
I love the mexican carvings into their hearts, stars, flowers etc.... I always wonder how they get such a nice finish on the material. I can polish obsidian well, but it usually requires a couple tries and cussing LOL.
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Post by jakesrocks on Jan 16, 2011 13:39:17 GMT -5
I have a piece of the neon blue and purple that was broken at a weird angle. Once the weather warms up, it will have to be glued to a block of wood, cut at 33 degrees to be able to cut it with the flow banding. If you have hard to hold pieces of material, this is a good way to get the proper cut on them.
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Post by Donnie's Rocky Treasures on Jan 16, 2011 15:20:21 GMT -5
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rockhound97058
freely admits to licking rocks
Thundereggs - Oregons Official State Rock!
Member since January 2006
Posts: 760
|
Post by rockhound97058 on Jan 17, 2011 12:23:47 GMT -5
Hey Donnie - Of course I could tell you much more if I had the piece in hand - but my best educated guess to cut your piece is - On your second picture, There's a flat face on your specimen on the left hand side. If it was me I'd cut parallel with that face and check to see what you have for a pattern. It's hard to tell 100% though. To me that kinda looks like silver sheen?
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Post by Donnie's Rocky Treasures on Jan 17, 2011 12:35:37 GMT -5
Thank you very much! Yes, it's supposed to be silver sheen. That's what I was told - me, don't think I would know the difference, but willing to learn!
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Post by jakesrocks on Jan 17, 2011 13:04:26 GMT -5
With the flow banding so distorted, just cut as close as you can to the banding. You may not get solid silver sheen across your cabs, but you'll get interesting swirls of the silver. I have some material very much like yours. When the weather warms I'll slab it. If I get some slabs with solid sheen, I'll send you one. Don
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Post by Donnie's Rocky Treasures on Jan 17, 2011 13:46:23 GMT -5
Thank you, Don! As soon as time permits I will tackle this one. Now I am really curious to see what it looks like!
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Post by jakesrocks on Jan 17, 2011 14:25:32 GMT -5
Cutting them is always the best part. You never know what treasures mother nature will present you with.
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Gem'n I
freely admits to licking rocks
Member since March 2008
Posts: 980
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Post by Gem'n I on Jan 19, 2011 16:11:16 GMT -5
Jason,
Thanks for taking the time to splain...my question revolves around rough...I bought a piece of rough that was sold to me as fire obsidian...it had no window or chip to see...how do you know what flavour you have when nothing is showing...I don't think the seller is going to let me whack away at his stuff and yet in rough form it is hard to decide if the price is worth the gamble...what is the best way to tell???
Larry
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Post by Jack, lapidaryrough on Jan 19, 2011 16:46:21 GMT -5
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Post by texaswoodie on Jan 20, 2011 9:11:20 GMT -5
I just cut my first piece of rainbow. When I made a cab the rainbow is visible at only a certain angle, the rest of the time it's solid black. Is it supposed to do this or do I need to adjust my cutting?
Curt
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Post by jakesrocks on Jan 20, 2011 11:07:32 GMT -5
You need to change your angle of cut a little bit. When properly cut, a cab will have a bulls eye effect when viewed from the front. You should get that flash of colors all the way across the cab when you turn it slightly. Polish a small window in a few places on the sides of your rough, and look for the bands. Cut as close to parallel to the bands as possible.
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Post by Jack, lapidaryrough on Jan 20, 2011 19:06:16 GMT -5
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Post by texaswoodie on Jan 20, 2011 19:58:36 GMT -5
Thanks Don!
Wow Jack, that is some beautiful stuff!
Curt
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