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Chipped opal


#1

Sure is heartbreaking to screw up! Hope somebody can help! I have
a beautiful stone that I was told is a “lemon opal”. I am pretty
ignorant about stones and can only describe this stone as a jelly
type opal, mostly a beautiful lemon colored translucent freeform
cab with some cloud like inclusions. It is shaped more or less like
a 3D sloped traingle with a ridge along the top. Of course when I
was trying to push the bezel around it I chipped a good part of the
ridge out of it. ARGH! I have probably made matters worse now, but
I attempted to reshape the stone (which wasn’t hard to do) and then
tried to polish it with ZAM, but can’t get the same gloss and/or
texture to match the rest of the stone. Anybody have any
suggestions? Thanks for your help!!! Mollie, in beautiful western
North Carolina,USA


#2

G’day. Mollie; I find that a slurry of tin oxide on a leather lap
rotating at around 800rpm works to give a brilliant polish on
nearly all stones, from agate to the soft ones like malachite and
lapis etc. Cheers,

   /\
 / /

/ /
/ /___| \ @John_Burgess2
(______ )
At sunny Nelson NZ


#3

Zam’s too aggressive I’d wager. Cerium oxide (optical grade #2)
usually does nicely on opal.

Carol


| Carol J. Bova @Carol_J_Bova |
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#4

Try tin oxide or chrome oxide for your polish. Believe it or not
you can also polish with diatomaceous earth. I’ve never tried the
last one, but have polished many an opal with chrome oxide on a
leather buff. Messy, but what a shine

There is no substitute for good manners except fast reflexes

Bobert
Carmel,CA


#5

Dear Mollie If the opal has been properly prepared for polishing,
so that there are no readily visible scratches on it, you can get a
great final polish with tin oxide. If you don’t have a lapidary
outfit, you can do the final preparation by hand by first sanding
the stone with 600 grit sandpaper and then emery cloth. Now mix a
paste of the tin oxide with water and coat either a felt polishing
wheel, or if you want to do it by hand, a piece of leather with
it. Then you can get a great polish on your stone (be careful not
to overheat the opal if you use the felt polishing wheel). Good
luck,Tom Tietze


#6

Mollie: We have used tin oxide to polish our yellow opal with great
success. I think that the lemon opal is the same. It should give it
a high shine. Hope this helps you. Micki Bleily
http://www.bleilysgems.com


#7

Mollie, I guess from your message that you don’t do lapidary work
so I hope this helps. Smooth the piece with a stone or perhaps 220
grit wet or dry paper depending on how badly it is chipped. Smooth
further with 320 and then perhaps 400 grit. Using a strip of
buckskin leather or something similar that is soft and pliable.
coat the leather with a creamy solution of cerium oxide or
aluminum oxide polishing powder and water. These are available
from any lapidary supply house. Holding the piece solidly in a
vise or something similar, buff the dull part of the stone until
you get an acceptable polish. Buff it as you would a shoe. Keep
the leather moist with the slurry. Jerry in Kodiak


#8

Hi Molly, If you have already reshaped the stone, you can easily
polish it with some diamond polish and a knife edge felt lap on
your flex shaft. It will take at least two grits, 600, and 1200,
and 3000. Be sure to clean well after each step.

			Duane,  Studio B
			Corbin,  KY

#9
   ... a "lemon opal"... Of course when I was trying to push the
bezel around it I chipped a good part of the ridge out of it.
ARGH! Mollie, in beautiful western North Carolina,USA

Molly,

Opals can be very anxiety-producing to set – I’ve cut and set a
lot of them. Prongs are difficult enough and bezels are especially
tricky. You know that now, unfortunately, so what do you do? If
you’re happy with the re-shaping you’ve done then it’s just a
matter of repolishing. My advice, unless you have lapidary
experience and equipment, is to take it to a local gem cutter
(there should be plenty in your area; look up members of your local
rock club. If you email me the name of your town or the nearest
large town I can probably find a contact for you). The process of
polishing stone is generally similar to polishing metal but
requires entirely different machinery, techniques, abrasives and
polishing agents. Zam just won’t polish opal, even if the stone’s
surface is sufficiently prepolished, and I suspect it isn’t. Most
cutting/polishing operations must be done wet to prevent heat
build-up, especially with opal.

The opal could be from Mexico, although there is a beautiful
yellow opal from central Idaho that is sold under the tradename
"Lemon opal." Similar opals occur elsewhere around the world.

Good luck.

Rick Martin in wet, dry, windy, calm, cloudy, sunny, warm, chilly
Ventura County, CA


#10
   I attempted to reshape the stone (which wasn't hard to do)
and then tried to polish it with ZAM, but can't get the same
gloss and/or texture to match the rest of the stone. Anybody have
any suggestions? 

Hi Mollie,

I would recomend contacting one of your local gem and mineral
clubs (there are quite a few in N.C. call your chamber of commerce
they should be able to help) There should be a number of people
there who will be able to recut your stone. It sounds like it may
be an American opal from up in Oregon. Usually that material has
inclusions like what you describe. You can repolish it yourself if
you have taken it to a fine enough grit with some cerium oxide on a
leather buff. You can contact me off list for more on
how to do this since opal is very easy to crack and this is some
what off topic. Barring all other solutions you can send the stone
to me and I can re-cut it, but first I would reccomend finding
someone local to save yourself the shipping charges. Feel free to
contact me off list if you have any questions.

Jason Penn
Jason Penn Designs
Your source for custom stone cutting
(520)793-3825


#11

Hi Mollie,

Let me assure you… its much more heartbreaking to screw up an
opal you cut yourself! Been there, done that!

Zam is probably not a great polishing compound for opal, like it
would be for turquoise or other soft stones. Cerium oxide or
aluminum oxide on leather or felt (kept damp) would probably have
a better result. Be especially careful to avoid overheating the
opal… keep it cool and damp.

Also, it’s important that the surfaces be very smooth and
scratch-free before you even attempt a polish. Like working with
metal, a poorly prepared surface will never yield an excellent
polish.

How was the show in Franklin last weekend?

Dave Sebaste
Sebaste Studio
Charlotte, NC (USA)
dave@sebaste.com
http://www.sebaste.com


#12

Hi, Mollie!

Getting a good, glassy polish on a stone can be tough,
particularly when the stone is soft or porous. The traditional
polishing technique for opal is to use tin oxide on a wet felt
buff, being careful not to let the stone heat up or the buff go
dry.(Some lapidaries prefer cerium oxide or linde A, but I’m
thinking Zam is just too coarse for the job at hand). No polishing
agent will help, however, if the stone was not first sanded with
succesively finer grits in order to remove any scratches. If you
have not already done this, try sanding the opal first with 400
grit wet paper, then with 600 grit, and then use tin oxide wet on a
felt buff,again being careful not to let the stone get hot.

If you still can’t get a good polish, then something else is
probably going on. I have had occasion to work on soft, porous
stones that would just not take a polish despite my every effort.
In such cases, consider using a hardener such as Hot Stuff
(basically superglue- cyanoacrylate) or Opticon. These substances
soak into the surface of the stone, then harden it enough to allow
for a good polish.

Hope this helps!

Lee
Dos Manos Jewelry
Phoenix, Arizona


#13

Hi Mollie, Zam won’t cut it. It might smooth the opal out alittle
but be warry not to get the opal hot when polishing. Better yet use
water cooled lapidary equipment and polish with tin oxide on a
leather lap.If the opal is of any value it would probibly be best
left up to someone local that you trust who has experience with
opal cutting. Chips happen to the very best of setters.

good luck
Don Wollwage


#14

Mollie, Where di you get the lemon opal? I’m trying to find
someone who carries it. I just returned from the G&LW show in
Orlando, Fl. and couldn’t find anyone who even knows what it is.
Can anyone out there tell me more about what lemon opal really is -
a true opal? or something else? It’s just a beautiful stone.
Thanks - Gini on the westcoast of Florida where it is in the 90’s
already


#15

Mollie, Where di you get the lemon opal? I’m trying to find
someone who carries it. I just returned from the G&LW show in
Orlando, Fl. and couldn’t find anyone who even knows what it is.

Hi Gini,

I am very curious who was selling this material in your area, I
have had three seperate inquires from your area of the U.S.
recently. There are quite a few different places this material
comes from. One is up in the Idaho-Oregon area it sounds like that
is the type of material Mollie has ( that matrial has typical
inclusions) Another newer find is in Africa and I have seen some
material that was claimed to be Austrailian. I have a friend who
handles the American variety I have some of the African variety
and I am not to sure about the Austrailian variety. If you are
interested in some cut stones please let me know. It is a natural
opal no dyeing or coloring and it is a very pretty yellow color. It
will be easiest to reach me by phone because I am leaving to go to
Chicago tomorrow for the Intergem show. (anyone please stop by the
booth to say hi #411) If you would like to wait to see some stones I
will be at the G&LW show in Franklin N.C. in July I don’t know the
booth number yet but I will post to the group closer to show date.
HTH

Jason Penn
Jason Penn Designs
Your source for custom stone cutting
(520)793-3825


#16

Gini, I bought several pieces of lemon opal at Tucson in February
from a company called EARTH LOVE, 3440 Youngfield street, Suite
353, Wheat Ridge, Colorado, 80053. Seller said it came from
Nevada. Jerry in Kodiak