October 3-7—JOSHUA TREE, CALIFORNIA: Annual show; Sportsmans Club of Joshua Tree
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 Post subject: Indonesian Opal - A New Find
PostPosted: Fri Apr 01, 2016 2:20 am 
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On Facebook lately we have been seeing a lot of jet Black Opal from Indonesia. Lots of it looks like wood replacement Opal so we decided to jump on a plane and go check it out. Even with the lack of communication we did learn a fair bit about this Opal. Here is what we found.

1) The mines are in isolated forest areas of Banten Indonesia
2) The conditions are hot. The mines are deep and there is a real lack of Oxygen down there (Especially since they continue to smoke underground)
3) The mines are full of black potch with no color. Finding color is rare
4) Two main appearances
- Black Opal with play of color, it is never as bright as most Australian or Ethiopian Opal but the actual potch is semi translucent
- Wood replacement apperance - This material is very interesting and more research is needed to get a better idea of what it is.
5) The material dries out very quickly. Wet the material, pick up the camera and by the time you take a photo it is almost dry. It does not seem to be hydrophane becuase this continually happens, it never becomes saturated.
6) It feels lighter than Australian or Ethiopian Opal. SG tests are still to come
7) Treatment - We observed two interesting things happening at the mine site. We could not communicate because of the language barrier but this is what we witnessed.
a) Everything was soaking in baby oil. We believe that this is because they were not able to get a good polish on the stone and so the oil was the only way to bring out the color. We also witnessed stones in foil, submerged in oil over a flame. We are not sure what this was doing but perhaps it was to try and keep the oily appearance on the Opal for a longer period of time.
b) "Natural treatment" - They would soak the Opal in water for 24 hours and then leave it in the sun for 1 week. This improved the intensity of the color. This need further investgation

We have some samples being sent to various labs for testing an inspection. Hopefully some more information will come to light soon. I will keep updating this thread as we find out more.


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 Post subject: Re: Indonesian Opal - A New Find
PostPosted: Fri Apr 01, 2016 12:39 pm 
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Very interesting!

You're a braver man than I in venturing down that unstable-looking hole :)

Look forward to hearing more.


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 Post subject: Re: Indonesian Opal - A New Find
PostPosted: Fri Apr 01, 2016 2:10 pm 
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Very interesting!!

I like esp. these items with parallel colorplay!!

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 Post subject: Re: Indonesian Opal - A New Find
PostPosted: Tue Apr 12, 2016 10:15 am 
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Very interesting Ross, thanks for sharing! I have been seeing this on the market, but with varying claims as to treatment level - some vendors claim 100% untreated, and some say it is sugared and or smoked. Please keep us posted if you learn anything more?

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 Post subject: Re: Indonesian Opal - A New Find
PostPosted: Mon Apr 18, 2016 5:14 am 
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Okay, that wood-grain texture makes it worthwhile to me.
Also, oiling it? :shock: You would think it wouldn't improve much but if it can lock the optimum amount of water in the stone...
There is too many good materials in Indonesia and often no easy way to acquire them uncut, it would be nice if someone who has the connections could set up a site to sell these materials online with a good portion of the proceeds given to the miners.


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 Post subject: Re: Indonesian Opal - A New Find
PostPosted: Wed Jun 13, 2018 2:38 am 
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Wood opal perhaps the worst ever opal... Cannot be polished properly and extremely unstable. But their solid opals (which are completely untreated) are different stories. Raw solid opal looks like Virgin Valley opal, their crystal and fire orange type looks like Ethiopia and Mexican, some of solid opaque black opal looks like black Australian opal..


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File comment: 5.9 cts Banten contra Luz opal
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File comment: 20.6 cts Banten crystal opal
IMG_20180610_130116_HHT-01.jpeg
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 Post subject: Re: Indonesian Opal - A New Find
PostPosted: Thu Jun 14, 2018 2:00 pm 
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Are you claiming the opal pictured above is Indonesian?


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 Post subject: Re: Indonesian Opal - A New Find
PostPosted: Thu Jun 14, 2018 8:37 pm 
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Barbra Voltaire wrote:
Are you claiming the opal pictured above is Indonesian?

Yes... I acquire thats opal directly from Malaysian owned Banten opal mine.


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 Post subject: Re: Indonesian Opal - A New Find
PostPosted: Thu Jun 14, 2018 8:43 pm 
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Iskandarman wrote:
Barbra Voltaire wrote:
Are you claiming the opal pictured above is Indonesian?

Yes... I acquire thats opal directly from Malaysian owned Banten opal mine.


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 Post subject: Re: Indonesian Opal - A New Find
PostPosted: Sun Jun 17, 2018 2:57 pm 
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May be a whole new mine. But...
My family lived in Jakarta during the 1970’s. My dad a geologist bought a number of polished opals at that time. Black, white, brown. Colors were good but all black and white spontaneously crazed into pieces eventually. The black would stick to your tounge. The brown were reverse hydrophone: lost play of color when wet then regained it as they dried. Could be different material but looks like the items pictured.


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 Post subject: Re: Indonesian Opal - A New Find
PostPosted: Mon Jun 18, 2018 5:22 am 
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mowgli2001 wrote:
May be a whole new mine. But...
My family lived in Jakarta during the 1970’s. My dad a geologist bought a number of polished opals at that time. Black, white, brown. Colors were good but all black and white spontaneously crazed into pieces eventually. The black would stick to your tounge. The brown were reverse hydrophone: lost play of color when wet then regained it as they dried. Could be different material but looks like the items pictured.

The first banten i have the wood-opal types. Very difficult to polish the wood without using resin. The Play of color from the opal parts is very very colorful just like the koroit. But most crazed after certain time but still preserve it's POC.
Wonder why solid Banten opal rarely seen in eBay etc? Perhaps consumer prefer the Well because of their price..


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 Post subject: Re: Indonesian Opal - A New Find
PostPosted: Tue Jun 26, 2018 11:02 pm 
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21 cts White opal from Indonesia in water. The opal doesn't change even stay underwater.


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 Post subject: Re: Indonesian Opal - A New Find
PostPosted: Tue Jun 26, 2018 11:12 pm 
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What does this material sell for?


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