4guys1me
off to a rocking start
Member since August 2011
Posts: 5
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Post by 4guys1me on Sept 5, 2011 20:13:50 GMT -5
I have some lapis lazuli I'm trying to tumble. I've used coarse grit for at least two weeks with no results. What can I use to get them rounded?
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blessed
spending too much on rocks
Member since January 2010
Posts: 329
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Post by blessed on Sept 5, 2011 20:50:27 GMT -5
I Have never tumbled lapis, but tell us the steps you used on the course grit. How much lupis, how much water, how much grit, and how big was the lopis. Any small stuff for carrying grit?-----James
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Post by Toad on Sept 5, 2011 23:15:18 GMT -5
Vibe or rotary? Lapis is pretty soft. Two weeks should have done significant work on those stones.
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jspencer
freely admits to licking rocks
Member since March 2011
Posts: 929
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Post by jspencer on Sept 5, 2011 23:20:43 GMT -5
I`d like to see what ends up working for you. I have collected quite a bit of lapis and want to polish it soon. I thought it needed to be stabilized like turquoise. I also got some nice lapis and malachite blend to try. Beautiful stones with no other matrix, just the solid "jewel" free of veins.
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4guys1me
off to a rocking start
Member since August 2011
Posts: 5
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Post by 4guys1me on Sept 5, 2011 23:49:07 GMT -5
I have a 3 lb rotary tumbler in which I have 5 rather large (about 1") pieces of lapis lazuli, each inbedded in a matrix. I used 1/4 cup of "Silicon Carbide Abrasive 60/90" and plastic beads the first week. No apparent progress was noticed. Second week I cleaned them and put more water (just above the layer before the top layer) with 1/4 cup of the same 60/90 grit and 1/2 the beads I had used the first week. Still no wear is apparent. Now I'm on the third week with the same amount of water and grit but no beads. I thought the lapis lazuli was about a 7 on the mohs hardness scale. Does anyone have any ideas as to what I can try next? Should I put in some gravel or other small rocks to help the wear it down?
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Post by Toad on Sept 6, 2011 0:57:19 GMT -5
Yes, what Geoff said...
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Post by NatureNut on Sept 6, 2011 6:34:57 GMT -5
You might try replacing most of the plastic pellets (save a couple tablespoons) with ceramics. They are almost just like small stones and are heavier than plastic pellets. Jo
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4guys1me
off to a rocking start
Member since August 2011
Posts: 5
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Post by 4guys1me on Sept 7, 2011 22:13:57 GMT -5
Thank you everyone. I will try your suggestions and get back with you. It'll be a few weeks of coarse before I can determine the results.
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bushkraft
having dreams about rocks
Public nuisance Number 1
Member since July 2011
Posts: 65
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Post by bushkraft on Sept 7, 2011 22:28:01 GMT -5
I have cabbed plenty of good quality Afgan lapis ..... it shouldn't require stabilizing but as mentioned it is fairly soft, and will not accept a top quality polish. The lapis/malachite material is probably man made, it would be very unlikely that genuine lapis would form in a copper rich environment.
Take care.
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jspencer
freely admits to licking rocks
Member since March 2011
Posts: 929
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Post by jspencer on Sept 9, 2011 0:59:43 GMT -5
Here is the lapis and "other" non-manmade stones. I`ll have to find some more comparable hardness stones to tumble with them to fill a barrel. Can chrysacola be put in with this? I have a lot of it. Would jasper be too hard to mix in? Attachments:
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jspencer
freely admits to licking rocks
Member since March 2011
Posts: 929
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Post by jspencer on Sept 10, 2011 0:19:20 GMT -5
OK.........my bad Bushkraft. It is a malachite/azurite mix. With lapis on the right. I got a little more of the mix today when I dropped a tumbler off at the shop I repaired for the manager there.
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bushkraft
having dreams about rocks
Public nuisance Number 1
Member since July 2011
Posts: 65
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Post by bushkraft on Sept 10, 2011 5:04:52 GMT -5
Glad that's sorted out I was concerned that you had been ripped off ..... A Chinese company is producing a blend of Lapis and malachite chips bonded together with resin, they are advertising the product on the web as being a "natural mix of lapis/malachite" when of course it is blatantly not, their argument concerning similar unlikely mixes (on another forum) is that the material used in the mix is natural so it is quite legitimate to use the term 'natural' in their ads.
The same company is selling cheap yellow serpentine beads as "yellow jade" yellow jadeite is very expensive and way out of the affordability range of the average person, the confusion here lies in the fact that the Mandarin word for stone translates into English as 'Jade' so to them any stone can be labelled as jade !!
Take care.
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4guys1me
off to a rocking start
Member since August 2011
Posts: 5
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Post by 4guys1me on Sept 19, 2011 22:01:39 GMT -5
UPDATE: My lapis lazuli has finally made progress. Quite a bit of progress really. I put other rocks (from some we bought which aren't identified except that they are tumbling rocks). All of them are now rounded! We just put fine grit in with all the rocks and will leave it for about a week. Wish us good luck please. Thank you for all your help.
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4guys1me
off to a rocking start
Member since August 2011
Posts: 5
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Post by 4guys1me on Sept 29, 2011 0:35:27 GMT -5
8/28/2011 update on Lapis Lazuli. I've tumbled the rocks for another week with other rocks and they are looking so good! We now have them in their pre-polish stage. Thank you so much to those who suggested putting more rocks in with them. Another question if you don't mind. Why will the hardest rocks shine before the softer ones?
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Post by connrock on Sept 30, 2011 8:01:10 GMT -5
The harder rocks are actually "scratching" the soft rocks so the hard rocks polish up while the soft ones won't!
If you look at the progression of each stage through a 10x jewelers loup you will see that after each stage the "grain' on the rocks changes from a rough surface to a smooth surface of tiny,tiny bubbly type "scratches"! The smaller you can get these 'scratches' the higher the shine.
In your case the lapis is only being used to carry the grit and or polish to rub against the hard rocks and while doing so it(the lapis) is only being "scratched' by the hard rocks!
It's OK to mix different hardness rocks in the 1st and maybe the 2nd stage but after that you MUST use the same hardness rocks or media or the soft rocks just won't polish up.
Kind of like trying to wax your car using 120 grit sand paper and not a nice soft cloth!
connrock
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