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Old Stock Chrysocolla, Mexican Turquoise, and Sodalite

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Author Topic: Old Stock Chrysocolla, Mexican Turquoise, and Sodalite  (Read 708 times)
Bruce
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« on: November 06, 2015, 05:38:11 pm »

I was able to get ahold of some very old chrysocolla from Inspiration Mine in Arizona, Mexican turquoise, and sodalite rough.  I've yet to work with any of these stones and thought I'd show them on here for recommendations on how to cut them into cabs.

I've seen quite a lot of information saying that the chrysocolla and turquoise should be stabilized before working with them and wanted to ask everyone's opinion on what is the best procedure to do so, or should it be done.  Should they be slabbed before stabilizing, or stabilize before slabbing?  The three small slabs of chrysocolla are all about 1 1/2" x 2".  The three rough pieces are about 4 inches long, and 2-3 inches wide.  Also, can any one id the other minerals that are present in these stones (I know it's hard from a picture)?

The Mexican turquoise looks like it may have amethyst on the top of it as well.  Is that common?  It is about 2 1/2" x 2 1/2 inches and almost as thick.  What is the best way to cut it?

I haven't worked with sodalite yet either.  It is about 4" x 3" and a little over an inch thick.  Any recommendations on it?


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Bruce
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« Reply #1 on: November 06, 2015, 05:39:27 pm »

Chrysocolla Rough


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Bruce
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« Reply #2 on: November 06, 2015, 05:40:25 pm »

Mexican Turquoise


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Bruce
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« Reply #3 on: November 06, 2015, 05:41:20 pm »

Sodalite


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PhilNM
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« Reply #4 on: November 06, 2015, 06:00:15 pm »

The turquoise doesn't look like it needs stabilizing. Try slabbing it and if it doesn't fall apart, then try cabbing it.
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Mark
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« Reply #5 on: November 06, 2015, 07:16:12 pm »

The first 3 slab or chunks, look like some really great Chrysocolla that i once had, that was hard and worked really well.  Its hard to say from the pics, but those 3 don't look like they need to be stabilized.  After working with a stone for awhile, you get a feeling for how it works and whether it needs to be stabilized or not.  The chunks are a lot harder to tell from the pictures and it will be really hard to tell whether they need to be stabilized.

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Bruce
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« Reply #6 on: November 10, 2015, 03:28:07 pm »

I decided to go ahead and cut without stabilizing, and everything cut really well.  I started cabbing a couple of the end cuts just to get a feel for the materials, and so far I really like working with all of them.  I've only sanded to 600, and still need final sanding and polishing, but I thought I'd show what they look like so far.


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ileney
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« Reply #7 on: November 11, 2015, 08:20:41 am »

This is a timely topic for me. Thank you for posting it. I also have some old (40 year old) chrysocolla that cut well. Some of it has polished up very evenly. However, the more colors in the stone, it seems like the less even the final polish. The stone below took a very high polish for the most part but when viewed at an angle, you can see that the surface is not even though it feels even to touch. The lighter turquoise is a bit lower and less polished (undercut?) Also, the very bright turquoise blue at the tip seems to have developed almost a white stress mark. I wonder if some people would stabilize this somehow and it would make it more even or if customers just view this as the character of the stone?  This was done on Nova wheels to 14,000.  (BTW, the line on the side that looks like it could be a fracture is silicated, not a flaw.) Thank you for your help to whoever can advise!


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Bruce
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« Reply #8 on: November 11, 2015, 03:38:07 pm »

Ileney -- I starting working on a few more cabs today, and haven't had any problems with undercutting.  These are only sanded to 600 so far, but seem like they'll take a good polish. 

I have noticed that the brighter blue parts seem to polish quicker than the surrounding stone.  If you aren't feeling a difference in smoothness, it could just be that like the ones I am working, the more colored parts are polishing quicker and only make it look like there is some light undercutting.


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ileney
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« Reply #9 on: November 11, 2015, 04:27:09 pm »

Thanks. No, I haven't had this problem with those stones that are only shades of blue, clear quartz and green, but run into it sometimes with the black, red and brown colors added to the mix. In this stone, only the light blue areas look like they are slightly undercutting; the brown/red, white, clear, green and darker turquoise areas all highly polished. I did not notice it until the 8,000, so I don't know if I just wasn't looking at it in enough light or if it actually showed up at that point. From any distance, the stone looks nicely polished, and I really only noticed it under magnification, so I might just leave it that way and accept it as a characteristic of the stone. I am not sure if there is something I can try that would not involve having to stabilize with Opticon and go through a whole rigamarole. I have more like this color and have only cut some of it, so I can't be sure it is all the same.  Are all your stones the blue color or do some have these other colors too?

I love the shapes you are cutting. The stones already look great for only 600. 

Please post pics of all your stones when you are done as I would love to see how they turn out after final polish.
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Debbie K
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« Reply #10 on: November 11, 2015, 06:13:25 pm »

I had the same issue with a piece of bloodstone; it was good at 1200 and okay at 3000, but when I hit it with the 8000 it began to orange peel like crazy. I actually kind of liked it, so I didn't bother to sand it out and do it over. This was on a carving with hard wood, oil and diamond, and I can only imagine how much worse it would have been on a wheel with any kind of give in it.

Some rocks are just cantakerous that way. Chrysocolla, jade and llanite in particular have bad reputations. Some people swear by spool polishers for polishing these troublemakers. But as I explained above, I don't think it would have worked on that piece of bloodstone.

I think that speed sometimes is a factor, too. I can't adjust the speed on my rock grinder/polisher, but I think a slower speed might sometimes be helpful. I once had a commission for an apatite carving, and every time I moved up to 1200 pieces would start lifting out. I ended up polishing the damned thing by hand from 600. It was a truly miserable experience.

The spool polisher does seem to work better on jade than the diamond belts on my grinder, but I think that heat makes some of the difference. I read an article years ago about the theory of polishing, and there was a school of thought that it wasn't possible to get a good polish on some stones using diamonds past a certain point. The diamonds, even the fine grits, slightly fracture the stone, and sometimes this causes problems. The more conventional compounds like Linde and cerium, they speculated, cause the surface of some rocks to actually flow. This article was directed primarily to faceters, but I thought that it may have implications for the rest of us.

Sorry you're having problems, but you might try stopping at 3000 with diamonds and try something else.

Debbie K
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ileney
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« Reply #11 on: November 12, 2015, 07:39:58 am »

Thank you so much for the advice Debbie!  I think I will bring it back to 3,000 or 1200 and see if it is no longer noticeable. I do have an (ancient and somewhat unreliable) flat lap with a slower speed setting and maybe I can try something on there for the higher grits/polish. I did notice this problem on a couple of other mutli-color chrysocolla stones, but only in a very tiny black pinpoint area that seemed to significantly undercut and almost dissolve. (I put those aside to treat at some point.) I did buy some Opticon a while ago just in case but have no experience with Opticon or any of the other stabilizers, so I am hesitant to do it if I can avoid it. I also have more of this old chrysocolla and a couple of new llanolite slabs I was going to try soon, so thank you for the heads up on that!
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Debbie K
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« Reply #12 on: November 12, 2015, 05:06:22 pm »

Found the thread with the bloodstone orange peel. Scroll down and there's a close-up showing it. I mentioned in the thread that it diminished when I decreased the pressure; maybe that will help, too.

http://gemstone.smfforfree4.com/index.php/topic,14915.0.html

Debbie K
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ileney
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« Reply #13 on: November 14, 2015, 09:32:02 am »

Thanks Debbie. Maybe I was pressing too hard. I'm going to try that and see.
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