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 Post subject: Chrome Oxide and Lapis Lazuli
PostPosted: Fri Oct 01, 2010 3:08 am 
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So, here I am, polishing the heck out of a slab of lapis lazuli with chrome oxide on leather, and what to my wondering eyes does appear? (Nope, not a fat guy with airborne livestock.) A rather nice shiny blue surface with green dots all over it! Not to mention the patina of green on the rough edges, which need to be rough lapis edges.

So the question: since running water and a toothbrush don't seem to get all the green off, does anyone have a trick for dissolving, floating, or otherwise removing chrome oxide from the cracks and crevices of a piece of lapis lazuli?

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 Post subject: Re: Chrome Oxide and Lapis Lazuli
PostPosted: Fri Oct 01, 2010 11:19 am 
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Have you tried an ultrasonic cleaner? Works pretty well on mineral samples and old clocks. If you don't have one maybe your local jeweler does. There are a bunch of these on E-Bay in the $50 neighborhood and they are great for cleaning all kinds of stuff.

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 Post subject: Re: Chrome Oxide and Lapis Lazuli
PostPosted: Fri Oct 01, 2010 5:46 pm 
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An ultrasonic will work well but be sure to run it with water only or a totally non-acidic solution. Lapis is a rock and it's usually associated with calcite and other carbonates. Even very diluted acid will destroy the polish in an instant. I know because it happened to me when I used a commercial ultrasonic cleaning solution.

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 Post subject: Re: Chrome Oxide and Lapis Lazuli
PostPosted: Sat Oct 02, 2010 7:22 am 
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Try dilute household ammonia in the ultrasonic. Ammonia will complex with chromium.


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 Post subject: Re: Chrome Oxide and Lapis Lazuli
PostPosted: Sat Oct 02, 2010 2:39 pm 
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Sounds like I am missing some equipment. Time to find an ultrasonic cleaner. Oh, boy, a Quest! :smt112

Thanks for the advice!

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 Post subject: Re: Chrome Oxide and Lapis Lazuli
PostPosted: Sun Oct 03, 2010 2:07 am 
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Found one. It seems to be doing the trick. Thanks again!

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 Post subject: Re: Chrome Oxide and Lapis Lazuli
PostPosted: Mon Oct 04, 2010 12:55 am 
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P.S. - Sue (my wife) wants to thank you, too. She loves the way her jewelry sparkles after a bath in the ultrasonic cleaner. \:D/

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 Post subject: Re: Chrome Oxide and Lapis Lazuli
PostPosted: Mon Oct 04, 2010 6:42 am 
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P.S. - Sue (my wife) wants to thank you, too. She loves the way her jewelry sparkles after a bath in the ultrasonic cleaner.


You know about Tanzanite, opal, and ultrasonic cleaners, right? Before something bad happens...


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 Post subject: Re: Chrome Oxide and Lapis Lazuli
PostPosted: Mon Oct 04, 2010 6:54 am 
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I was just thinking of sending him here
gemologyonline.com/Forum/phpBB2/viewtopic.php?f=37&t=12308 :wink:
You might want to check out ionic cleaners Steve.

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 Post subject: Re: Chrome Oxide and Lapis Lazuli
PostPosted: Tue Oct 05, 2010 3:37 am 
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Gearloose wrote:
Quote:
P.S. - Sue (my wife) wants to thank you, too. She loves the way her jewelry sparkles after a bath in the ultrasonic cleaner.


You know about Tanzanite, opal, and ultrasonic cleaners, right? Before something bad happens...

We know about opals, (we have only one) and included or filled stones (a nice pair of emeralds that came back from a jeweler looking shockingly dull comes to mind) but I didn't know about tanzanite. Have to file that away for when we get some. Thanks

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 Post subject: Re: Chrome Oxide and Lapis Lazuli
PostPosted: Tue Oct 05, 2010 11:50 am 
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Gearloose wrote:
You know about Tanzanite, opal, and ultrasonic cleaners, right? Before something bad happens...


There's long list of gemstones that can suffer damage in ultrasonic cleaners, including such common ones as rutilated quartz and included sapphires (broken both myself). In fact, anything with inclusions is vulnerable. The more powerful the ultrasonic cleaner, the higher the risk.

Duncan


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