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 Post subject: How to start with opals
PostPosted: Mon Nov 18, 2019 5:17 am 
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I am saving these beautiful opals for when I do know what I am doing with them but where do I start in polishing cutting practice?

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 Post subject: Re: How to start with opals
PostPosted: Fri Nov 29, 2019 3:36 am 
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I re-read my post :roll:

I should explain what material should I practice on before I start working with opals? Is there a cheap, lower grade of opal that I can practice on?
And how do I stabilize an opal before cutting and polishing?


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 Post subject: Re: How to start with opals
PostPosted: Fri Nov 29, 2019 3:49 am 
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I re-read my post :oops:

I should have asked what kind of material should i practice on before I touch a real opal. Is there a certain stone that is affordable that I need to practice on first? A cheaper type of opal that i could use until I know what I am doing?

Plus I have searched to find a tutor and or classes to get me started in cutting and polishing but I can't find one close enough and affordable.


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 Post subject: Re: How to start with opals
PostPosted: Fri Nov 29, 2019 11:04 pm 
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Opal is an odd beast, and you'll find that different types cut differently. It looks like you have a variety of stones from Welo in Ethiopia.
Upsides to opal, it is soft so it cuts fairly fast, and it's very easy to quickly polish to a mirror finish with cerium or tin oxide.

Downsides: heat sensitivity (don't let them get too hot!), sometimes will absorb water, in some cases might fall apart in cutting (quite unlikely for the type you have)

You can certainly get cheaper common opal from a variety of locations, but you will likely find it cuts very differently from your precious opal anyway. If you've only cut hard/tough stones like agates and jaspers before it would make sense to get some experience with softer stones like variscite, common opal, obsidian etc before you take on the opal, but mechanically it isn't fundamentally different from cutting anything else. Ethiopian opals sometimes need careful orientation for best patterning to the fire, but these look like they'll probably be fine from any orientation. These ones will probably absorb the coolant water as they cut, likely turning very clear, and they may turn cloudy after they're out for a bit. After a day (or up to a week sometimes) they will likely return to their original base color and clarity.

At the end of the day, Welo opal rough isn't that insanely expensive. Don't let it intimidate you too much--if you need to cut one or two practice pieces to get the hang of soft stones certainly do so, but the best way to practice will be to actually cut some. The sooner you get them cut, the sooner you find out if you like the results and want to do more, a good idea to do while rough is still easy to source and relatively affordable.

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