Item Information

Dimensions (mm) 40 x 21 x 5mm
Weight (carats) 30 carats

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This is  natural opal that is in the sandstone found on the boulder opal fields in Queensland.It has been treated to appear like black opal by being carbonized.

The workmanship  is excellent.

Silver bail stamped 925.

Weight  of stone 13.50 cts app

Weight of silver 16.50 cts app

Size 40 x 21 x 5 mm app

Our jewelery manafacturing is contracted out to one factory in asia where i supply  both the silver and stones to be set.This gives me control of  the quality of both the silver and stones.


What is Sandstone Opal Matrix?
Naturaly formed sandstone opal matrix is Precious Opal flecks dispersed throughout an earthy orange ferruginous sandstone.
Why is sandstone opal matrix treated?
By enhancing the background matrix will give a greater contrast thus the visability of the precious opal colors is greater and stabilizing the sandstone also strengthens the stone by up to x10. Once enhanced some stones have the appearance of top gem quality black opal particularly ones with interesting and unique patterns. They are also similar in appearance to Honduran (basalt) matrix and gem Andamooka (concrete) matrix, even nicer.
How is sandstone opal matrix treated?
The treatment is done by cooking the stone in sugar, thus the sugar is carbonized giving the stone a darker or black background and it is stabilized with inert chemical that strengthens the opal by up to x10. Only the sandstone absorbs the treatmeant, not the precious opal. This type of treatment when applied correctly is absorbed all the way through the entire stone, so re-cutting is not a problem, you do not have to treat it again after cutting.
This stone is a more compacted sandstone type and the flecks of precious opal are more concentrated. It takes a polish/ finish much better than the very porous types. 



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Pricing & Details

Bid Increment $1
Starting Bid $40
Auction ID 289119
Watchers 6 watching
Viewed 946 times
Starts 8th Oct 2017 9:00pm PDT
Ends 9th Oct 2017 8:24am PDT

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