How to clean opals
Sali Cosford Bonazelli
Hi, all...
I have a bunch of Mexican opals still embedded in rock. Can anyone tell
me how to get them out? I've had them for years and gotten no help from
jewelers. Thanks!
Sali in Connecticut
David M. Childers
Sali,
Unfortunately, in my experience the matrix is often harder than the
opal. So hand cobbing is usually risky.
I use a 4" 0.04" kerf saw (Little Rascal) with a water/detergent
coolant to cob the opals out if the opal is large enough.
Otherwise, I slab the matrix with the enclosed opal and cab the mix.
The matrix usually polishes well along with the opal and can make a
very interesting stone for setting.
Vincent King
Sali Cosford Bonazelli wrote:
>
> Hi, all...
>
> I have a bunch of Mexican opals still embedded in rock. Can anyone tell
> me how to get them out? I've had them for years and gotten no help from
> jewelers. Thanks!
>
Should you be referencing the Mexican Jelly Opal, embedded in a pinkish
to light brown matrix, why remove it at all? Cut and polish the
material in situ. They make exceedingly beautifull gems!
Trying to seperate the opal out endangers the stone. On top of that if
you have fire in the jelly opal, and destroy the stone while trying to
remove it........
If you're dead set on getting them out, I suggest using either and
fordum, or dremmel with diamond bits. Go slow and work away from the
gems.
Hope it helps
Vince
Andrew Werby
[I have cut a lot of these, and have had no big problems. They make
excellent small stones for everything but rings, as they are somewhat soft.
But removing them from the matrix did not destabilize the stones- I have had some that have been set in jewelry and kept dry for yea=
rs that are not crazing.
These opals range from clear to orange, often with intense fire, and are quite
different from the more familiar Australian white opal material. I have had
best results by carefully sawing out the largest areas of opal, dopping with
hot wax, then slowly grinding away the matrix to reveal the stone. You will, of
course, need lapidary equipment to do this, and must take care not to remove
too much- the material is soft and it is easy to grind it away to nothing. If the spots of opal are really too small to cut out, you=
can polish the whole lump, matrix and all, but this will produce an extremely soft stone with only spots of opal here and there- I =
don't like these much.
After sanding, I have had good luck polishing with cerium oxide on a chamois
wheel. I used to see a lot of this material at low prices, but not much any
more- perhaps the Mexicans are cutting it themselves, or are exporting all
the rough to be cut for their own use, I'm not sure which.
Andrew Werby - United Artworks
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