vance71975
freely admits to licking rocks
Member since September 2022
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Post by vance71975 on Oct 7, 2022 16:23:05 GMT -5
I know Green Opals are soft, should I still use 80 grit SiC or should I start them with 220 grit SiC? I am planning to get Marbles to use as Media with them as glass is the same hardness, is there any reason this would be a bad Idea? Any other tips, tricks and advice for Green Opals is very welcome!
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Post by vegasjames on Oct 7, 2022 17:10:50 GMT -5
I tumble my opals with just water. Never used grit with them.
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vance71975
freely admits to licking rocks
Member since September 2022
Posts: 760
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Post by vance71975 on Oct 7, 2022 20:09:24 GMT -5
I tumble my opals with just water. Never used grit with them. How exactly do they cut,shape and polish that way? I am a bit confused now.
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Post by vegasjames on Oct 7, 2022 22:34:44 GMT -5
It still grinds, just a little bit slower without the grit, which is great as the opal is softer.
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vance71975
freely admits to licking rocks
Member since September 2022
Posts: 760
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Post by vance71975 on Oct 7, 2022 23:05:44 GMT -5
It still grinds, just a little bit slower without the grit, which is great as the opal is softer. So would it hurt to start with a higher grit tho? Say 220 or 500 SiC?
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Post by vegasjames on Oct 8, 2022 0:40:50 GMT -5
If you want to try grit I would use a very fine grit and check on them often. Keep in mind that grit is much harder than even chalcedonies like jaspers and opal is much softer than chalcedonies. Therefore the grit is going to act on the opal way faster than chalcedonies.
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vance71975
freely admits to licking rocks
Member since September 2022
Posts: 760
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Post by vance71975 on Oct 8, 2022 0:59:18 GMT -5
If you want to try grit I would use a very fine grit and check on them often. Keep in mind that grit is much harder than even chalcedonies like jaspers and opal is much softer than chalcedonies. Therefore the grit is going to act on the opal way faster than chalcedonies. Gotcha so check every couple days if using very fine grit.
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Post by vegasjames on Oct 8, 2022 1:51:24 GMT -5
I would check daily. Even when I tumble my opal with just water I only tumble them for about 3 days and there is a lot of finely ground opal in there. With the silicon carbide being so much more abrasive I would check daily until you get a feel for that opal as opal can vary in hardness so some opal will grind faster than other opals. All depends on water and aluminum oxide content of the opal.
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vance71975
freely admits to licking rocks
Member since September 2022
Posts: 760
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Post by vance71975 on Oct 8, 2022 2:25:41 GMT -5
I would check daily. Even when I tumble my opal with just water I only tumble them for about 3 days and there is a lot of finely ground opal in there. With the silicon carbide being so much more abrasive I would check daily until you get a feel for that opal as opal can vary in hardness so some opal will grind faster than other opals. All depends on water and aluminum oxide content of the opal. Since I only have 1lb of Green Opals, and a 4lb barrel, would Marbles(glass and about a 5 hardness as well) an ok Media instead of Ceramic(since ceramic is a 7 hardness) ?
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Post by vegasjames on Oct 8, 2022 2:58:45 GMT -5
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vance71975
freely admits to licking rocks
Member since September 2022
Posts: 760
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Post by vance71975 on Oct 8, 2022 3:04:56 GMT -5
Oh damn those are some NICE STONES! Ya see I only have 1 lb of Opal, not enough to fill my barrel even 1/4 the way up and I am aiming for a mirror Shine when im done not just cleaning them. I dont have a saw or cab machine as of yet so I am just tumbling.
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nursetumbler
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Post by nursetumbler on Oct 8, 2022 7:40:12 GMT -5
I would check daily. Even when I tumble my opal with just water I only tumble them for about 3 days and there is a lot of finely ground opal in there. With the silicon carbide being so much more abrasive I would check daily until you get a feel for that opal as opal can vary in hardness so some opal will grind faster than other opals. All depends on water and aluminum oxide content of the opal. vegasjamesAm I reading this post right? Opal has aluminum oxide IN it??? Maybe thats why water only works well. I have Peruvian opal from I think catmandewe. Can't wait to do it now. vegasjames. Would that method work for all soft stones like fluorite and calcite?
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Post by vegasjames on Oct 8, 2022 8:02:00 GMT -5
I would check daily. Even when I tumble my opal with just water I only tumble them for about 3 days and there is a lot of finely ground opal in there. With the silicon carbide being so much more abrasive I would check daily until you get a feel for that opal as opal can vary in hardness so some opal will grind faster than other opals. All depends on water and aluminum oxide content of the opal. vegasjames Am I reading this post right? Opal has aluminum oxide IN it??? Maybe thats why water only works well. I have Peruvian opal from I think catmandewe . Can't wait to do it now. vegasjames . Would that method work for all soft stones like fluorite and calcite? Most opal does have varying levels of aluminum oxide. The source can be biogenic or inorganic. The biogenic opals get the aluminum oxide from diatoms and rotorlarians. For example, the chemical make up of diatomaceous earth is roughly 80% silicon dioxide, 10% metal oxides including aluminum oxide and 10% moisture. Opals from inorganic sources often get their silica and aluminum oxide from the clays they form in. Since the level of aluminum oxide can vary, so does the hardness of the opal.
Opals can also contain various other elements and compounds such as uranium, barium, etc that are often nucleators for the formation of opals.
I have tumbled softer stones this way as well again just to clean them up. The softer stones will not polish well in the tumbler. But I often do this with the copper-silver ores that the matrix is primarily softer dolomite, limonite (mix of iron oxides and hydroxides), and minor calicite. As well as the Nevada Tiffany stone, which has a matrix usually composed primarily of dolomite and minor calcite with all the purple fluorite. Some pieces have a much higher quartz content. Tumbling these removes a lot of the white matrix and limonite and leaves behind more of the colors i am looking for. Some of the pieces I can then shape on the cabbing machine, or I trade them to a guy in Michigan who puts the stones in jars of water to bring out the colors more.
I have also experimented with tumbling some of the selenite I dig up including the red selenite. Problem with this one is they form in plates and the plates tend to separate. Still pretty cool after a day or so to see the rounded off pieces.
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Post by vegasjames on Oct 8, 2022 8:05:02 GMT -5
Oh damn those are some NICE STONES! Ya see I only have 1 lb of Opal, not enough to fill my barrel even 1/4 the way up and I am aiming for a mirror Shine when im done not just cleaning them. I dont have a saw or cab machine as of yet so I am just tumbling. Maybe we can work out a trade. I can send you a bunch of opal so you can fill your barrels n exchange for some of the finished opal back. I would be very interested to see how the opal looks tumbled more normally. Will be busy the next couple of days though and will not be on the computer much if at all. So I will check back when I get a chance.
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vance71975
freely admits to licking rocks
Member since September 2022
Posts: 760
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Post by vance71975 on Oct 8, 2022 14:01:46 GMT -5
Oh damn those are some NICE STONES! Ya see I only have 1 lb of Opal, not enough to fill my barrel even 1/4 the way up and I am aiming for a mirror Shine when im done not just cleaning them. I dont have a saw or cab machine as of yet so I am just tumbling. Maybe we can work out a trade. I can send you a bunch of opal so you can fill your barrels n exchange for some of the finished opal back. I would be very interested to see how the opal looks tumbled more normally. Will be busy the next couple of days though and will not be on the computer much if at all. So I will check back when I get a chance. well I need to get my tumble done on my cheap green opals first because I dont want to mess up anyone elses stones. Plus I need some expirence under my belt before I tackle opals which is why i was asking now, its gonna be at least a month or two before I even tackle my cheap opal lol
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Post by vegasjames on Oct 8, 2022 21:40:57 GMT -5
I would not worry about messing up my opal. I have hundreds of pounds of opal. It is so common in Nevada that I am surprised it is not our State stone.
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nursetumbler
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Post by nursetumbler on Oct 8, 2022 22:05:28 GMT -5
I would not worry about messing up my opal. I have hundreds of pounds of opal. It is so common in Nevada that I am surprised it is not our State stone. vegasjamesAre you interested in selling any of your opal? If so I'd be interested. I have the pink opal.
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Post by vegasjames on Oct 8, 2022 22:30:07 GMT -5
I would not worry about messing up my opal. I have hundreds of pounds of opal. It is so common in Nevada that I am surprised it is not our State stone. vegasjames Are you interested in selling any of your opal? If so I'd be interested. I have the pink opal. Yes I can sell some.
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Post by vegasjames on Oct 8, 2022 22:38:40 GMT -5
All these bins and the garbage can are full of just some of my opal collection.
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nursetumbler
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Post by nursetumbler on Oct 8, 2022 22:45:49 GMT -5
All these bins and the garbage can are full of just some of my opal collection. vegasjamesWOW!!!! I tumble mostly and would love some to tumble.
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