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October 31, 2014, 09:25:40 am
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Rainbow Obsidian

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Ranger_Dave
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« on: November 20, 2013, 08:55:13 pm »

I have 5 fist size pieces of rainbow obsidian. How do I cut slabs off in order to get the best rainbow? What's the better cab for this stone; high dome or flat?
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catmandewe
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« Reply #1 on: November 20, 2013, 09:14:30 pm »

Depends on if you want flash all the way across or you want to make cats eye cabs. Also depends on if the color layers are flat  or wavy.
If you want flash you need to cut anywhere from 5 to 20 degrees off of parallel to the color bands, the degree of cut will determine how many color bands you cut through and also how far apart the color bands will be from each other.
If you want cats eye cabs then you want to be perfectly parallel to the color bands and then when you dome it the top color will be the cats eye. If your bands are flat it can work, but it does not work everytime.
If your color layers are wavy then it all depends on how it is oriented and the wavy section may change from one side to the next.
It is mostly a hit and miss thing. One good way to find the color band is to take small flakes or chips off of your material with a small hammer or bopper until you find the color you want, then cut parallel to that flake face. Each slice will be different since you are cutting into the next set of color bands and they may be different colors. A little bit too much or too little and you will lose it again.

Experiment with it, it is supposed to be fun.
I do the flake thing and set it up for the best flash then I cut the whole thing and hope it comes out, some do, some don't. If you lose it you can change angles but that all takes time and each change makes a mostly unusable piece so I find it better to just cut it and hope I get some good ones. The good ones are good for cabs and the crappy ones I save for flintknappers as when they flake them the planes change anyways so it can still work.

Good luck with it but most importantly,
Have fun with it.................Tony
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Ranger_Dave
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« Reply #2 on: November 20, 2013, 10:13:29 pm »

Thanks. I didn't know about the cats eye bit. That sounds interesting. From the sides the layers look like they are all flat and really close together, less than 1/16 of an inch.  I'll have to try both ways and see what happens. This will be fun. The pieces that aren't good enough for cabs I can always make arrowheads or knife blades out of.
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sealdaddy
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« Reply #3 on: November 21, 2013, 08:42:03 am »

Cat's eye is one way of putting it, but I call that bull's eye.
I do it with every banded material I find.
It is Very cool looking~!


* bulls eye.jpg (17.87 KB, 340x270 - viewed 213 times.)

* bulls eye1.jpg (4.92 KB, 252x200 - viewed 196 times.)

* bulls eye2.jpg (13.81 KB, 230x300 - viewed 196 times.)
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bobby1
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« Reply #4 on: November 21, 2013, 10:33:55 am »

Cats eye Obsidian.


Bob
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bobby1
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« Reply #5 on: November 21, 2013, 10:36:13 am »

If you can get a copy of the June 2010 Lapidary Journal there is an article on how to orient Rainbow Obsidian for the cats eye effect.........I wrote it.
Bob
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Ranger_Dave
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« Reply #6 on: November 21, 2013, 04:16:55 pm »

Those are beautiful. I'm going to have fun with this stuff. I'll look for that issue of that magazine. I might have to subscribe too.

It looks like cutting along the layers and a high dome will get me the bullseye.
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PanaMark
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« Reply #7 on: November 21, 2013, 05:14:12 pm »

If you can get a copy of the June 2010 Lapidary Journal there is an article on how to orient Rainbow Obsidian for the cats eye effect.........I wrote it.
Bob

Bob, didn't you or Krystee post a tutorial on that some time ago on here? I can't find it right now, but it was very good.
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- Mark

Trying to see the potential in every rock (and everybody).
bobby1
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« Reply #8 on: November 21, 2013, 06:16:12 pm »

Mark,
I don't recall the tutorial but it could have been me.
Dave,
Cutting parallel to the color bands will give you a bullseye if the cab is round. Getting the catseye is a little more involved. You  have to look carefully for minute parallel "fibers" in the color layer and ensure that they are oriented across a long narrow cab like in the photos. The slab has to be almost 1/2" thick so as to provide some dark, density to the cab to prevent transmitted light from diminishing the eye effect. The cab has to be rather narrow with a high dome. This allows the light to roll across the cab and enhances the light reflection off the parallel "fibers".
Bob
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rocks2dust
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« Reply #9 on: November 21, 2013, 08:10:13 pm »

And sometimes you get lucky and find a piece that has a natural cat's eye that displays on a flat or low dome:
Since the alternating thin clear and sheen layers are already tightly curled, this type is sort of the opposite of doming a piece with parallel banding.
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r2d
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« Reply #10 on: November 21, 2013, 08:25:45 pm »

Cutting parallel to the color bands will give you a bullseye if the cab is round. Getting the catseye is a little more involved. You  have to look carefully for minute parallel "fibers" in the color layer and ensure that they are oriented across a long narrow cab like in the photos. The slab has to be almost 1/2" thick so as to provide some dark, density to the cab to prevent transmitted light from diminishing the eye effect. The cab has to be rather narrow with a high dome. This allows the light to roll across the cab and enhances the light reflection off the parallel "fibers".
Bob
Ah, I get it now. Round for a bulls eye, but elongated for a cats eye.  A high dome wold be essential for the effect on either.
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phishisgroovin
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« Reply #11 on: November 21, 2013, 09:17:12 pm »

I love working with it, beautiful stuff and its hard to mess up the rainbow.

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tntmom
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« Reply #12 on: November 21, 2013, 11:24:13 pm »

If you can get a copy of the June 2010 Lapidary Journal there is an article on how to orient Rainbow Obsidian for the cats eye effect.........I wrote it.
Bob

Bob, didn't you or Krystee post a tutorial on that some time ago on here? I can't find it right now, but it was very good.

It wasn't me.  Cat's Eye cuts are my favorite with Obsidian but Bobby taught me everything I  know about cabbing it!!!! yes yes yes  (My avatar is a Davis Creek Cat's Eye!!!)
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~Krystee

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« Reply #13 on: November 21, 2013, 11:30:19 pm »

And.... here is what it looks like in motion!

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~Krystee

Works at:  http://www.earthlightgems.com/
Proud member of East Kingco Rock Club:  http://www.eastkingco.org/index.php

Yesterday is history.  Tomorrow is a mystery.  Today is a gift, that's why it's called The Present.

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« Reply #14 on: November 23, 2013, 04:47:48 pm »

Yeah, Bobby I found it and it was you. It was a real good tutorial and I bookmarked and printed it.

it is here:  http://gemstone.smfforfree4.com/index.php/topic,2438.0.html
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- Mark

Trying to see the potential in every rock (and everybody).
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