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Post by mohs on Oct 5, 2020 17:25:50 GMT -5
have no experience working with opal I have this little chunk 2 x 2 and ½” thick feels solid and dense  I want to slice off the marked part trim saw w/ a 6“ LapCraft Dia blade .012 kerf blade as thin as they get, I think is this material liable to crumble/ crack in the cut.? What’s your best guess ? Thanks guys Ed |
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Post by amygdule on Oct 5, 2020 17:37:01 GMT -5
You should be OK.
Opal is softer than agate.
Just take it slow and easy.
I use a 6" x .006 kerf blade for cutting gem materials.
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Post by mohs on Oct 5, 2020 17:40:59 GMT -5
cool dule
I might need to get that thinner blade
or
I have a band saw
hmmm....
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Post by hummingbirdstones2 on Oct 5, 2020 19:22:17 GMT -5
Your chunk doesn't appear to have any really jagged edges or visible cracks. You should be okay. For the rough I'm seeing, the .012" blade is okay. You won't miss the other .006", and sometimes the extra stiffness of a slightly thicker blade help with keeping the cut straight.
If you have a small, really bright LED light (mini Mag Light type or similar) dim the room lights and hold the light against the back of the chunk. It should light the piece up like a halloween pumpkin. Cracks show up pretty easily like that. Sometimes you can also see sand blobs or other inclusions as shadowy areas.
Hope you don't see anything too scary if you backlight the piece. If you do, at least you might be able to plan a different way to slice it.
Let us know how it goes...!
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Post by mohs on Oct 5, 2020 20:23:13 GMT -5
Thanks Vince
good info
I'm holding it up to regular light
and do see a nice bluish tinge
get a LED light later
that will be interesting
never cut or polished opal
hoping to use the opal half for a birthstone combo
have feeling I'm in for a big challenge
as the other half is quartz crystal
two vastly different hard mohs
to polish together
Thanks!
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Post by pauls on Oct 5, 2020 20:51:55 GMT -5
After you have cut that where it's marked cut another piece and have a practise. If the Opal is good (not cracked) you should have no trouble. Be careful not to get it hot, that's about the only thing you need to worry about. You probably wont have any trouble with your project either, Opal and Quartz cut much the same even if their hardnesses are a bit different. Or you could make the opal into a triplet with a Quartz top, that would eliminate any difference completely.
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Post by mohs on Oct 5, 2020 20:58:31 GMT -5
right on !
that an excellent idea pauls !
one I hadn't thought
of
I'm getting good at grinding 2 different mohs together
and keeping the heat down mostly
Thanks !!!
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Post by hummingbirdstones on Oct 5, 2020 21:04:37 GMT -5
Vince and Paul gave you great advice, Ed. You should be good to go. Don't use 80 grit on the opal. Go up to the next higher grit you have. It will work fast so go slow, light touch and you'll be groovy.
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Post by mohs on Oct 5, 2020 21:14:24 GMT -5
right on Robin stay off the 80 I'll be tempted to touch that quartz crystal with the 80 acutaully I just bought a new 220 grit  a very wise excellent rock polisher stated once Life to short to use worn out diamonds  well us rock bottom guys have to grind with the resources we have but that new 220 makes a BIG differnce it an April/October combo April birthstohn is diamond but I'll take shortcut with crystal |
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Post by hummingbirdstones2 on Oct 6, 2020 7:48:11 GMT -5
A brand-new 220 might still be a little "scratchy" for opal.
The suggestion about working a different piece first to see how it goes will be the way to know for sure.
The "worn-out diamonds" really are good (up to a point) for opal.
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Post by hummingbirdstones on Oct 6, 2020 8:09:34 GMT -5
Work the quartz on the 220 before you use it on the opal. That way any high spots should get knocked down. Maybe even use a spare piece of something to work on that new one first so you don't get a big old gouge in your opal.
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Post by orrum on Oct 6, 2020 9:29:22 GMT -5
Whack it Ed, cut that baby open and let's see inside!!!
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Post by mohs on Oct 6, 2020 13:10:21 GMT -5
alright guys
the slicing went well
now the forming and shaping
been planning this birthstone heart
for 6 month
now I got 2 weeks to finis`
till the wedding
no broken points !
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Post by mohs on Oct 9, 2020 15:05:21 GMT -5
What are some of recommended methods
for the final polish of opal?
thanks
mohs
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Post by pauls on Oct 9, 2020 15:43:35 GMT -5
What are some of recommended methods for the final polish of opal? thanks mohs The Opal cutters in Oz use Tin oxide on felt, at least they used to, I haven't been to the Opal fields and looked over someone's shoulder for a while. Cerium oxide is excellent too. What have you got there Ed? Whatever, it will probably be OK, Opal is nice stuff to work. Edit to add. Whatever you use keep it wet to avoid heat. |
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Post by mohs on Oct 9, 2020 16:40:04 GMT -5
Yeah I got the heart ground up to 800 grit So the hard part is pretty much done About 4 more polishing grades to go I’m pretty happy with how its shaping and shining. The opal now-- is a bit weak in the glitter department But its nice & I expect the glitter to only increase. Hopefully if I achieve a more refined finish Thanks so much paulsReally appreciate the response & hope its rolling smmoootthhhhh... Ed |
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Post by hummingbirdstones on Oct 9, 2020 19:47:29 GMT -5
I use optical cerium (the white stuff) on leather that I wet with water to polish opal. Take it off the lap frequently to keep it from getting too hot. I usually keep a container of water by me to dunk the opal in during polishing to cool it off.
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Post by mohs on Oct 9, 2020 20:22:09 GMT -5
Right on Robin
Yeah that not getting certain stohns hot in the polish stage
That burned me also before.
As mentioned it shaping up nicely
Sure under a loupe it would be a fail
To get the most out it I probably should
dop it
The opal side is fairly large.
Sided up with a half of mostly clear milky quartz.
Had a little pitting. I use some super glue on.
Seems like it blended well.
It mostly done
Yet still a long ways to be hung.
So fingers crossed.
Hearts are risky.
It been a project that I hope shines….
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Post by hummingbirdstones on Oct 9, 2020 21:01:31 GMT -5
Opal shines up real easy, Ed, if you make sure all your scratches are out on the previous grits. Couple seconds worth of polishing with cerium, really.
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Post by mohs on Oct 10, 2020 10:02:50 GMT -5
Thanks Robin ! I just did a re-doming kind of a finesse re-work through to the 800 grit touchy now on2 the final stages fingers crossed well... not while I 'm grinding m  stly |
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stly 
