thomtap
starting to spend too much on rocks
Member since December 2007
Posts: 237
|
Post by thomtap on May 15, 2009 7:59:51 GMT -5
I just got a few pounds of both. Can I tumble them together? Any suggestions about getting a great shine with them?
Thanks!
Thom
|
|
chassroc
Cave Dweller 
Rocks are abundant when you have rocktumblinghobby pals
Member since January 2005
Posts: 3,586
|
Post by chassroc on May 15, 2009 8:05:15 GMT -5
I think Fluorite is too soft to tumble
csroc
|
|
|
|
Post by 150FromFundy on May 15, 2009 10:13:56 GMT -5
Chassroc is correct that Florite is soft. Mohs hardness 4. I have never seen it tumbled. Just nice crystals and specimen pieces.
Obsidian isn't much harder with a Mohs hardness of 5. Obsidian is volcanic glass and has the same hardness as manufactured glass. Obsidian can be worked beautifully, but requires slightly different techniquers that some of the veterans of RTH can probably help you with.
150FromFundy
|
|
thomtap
starting to spend too much on rocks
Member since December 2007
Posts: 237
|
Post by thomtap on May 15, 2009 11:44:42 GMT -5
I didn't know you couldn't tumble fluorite. I guess I wasted my money on that then! I was hoping to cab it, and tumble polish it. Oh well, live and learn! No use for the stuff now!
Any tips on the obsidian?
|
|
Rogue Trader
freely admits to licking rocks
"Don't cry because you are leaving, smile because you were there."
Member since December 2008
Posts: 839
|
Post by Rogue Trader on May 15, 2009 11:51:33 GMT -5
Flourite can be tumbled, it has a hardness of 4, and obsidian has a hardness of 7.
Because of the big difference in hardnesses I don't think you would be able to tumble them together.
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on May 15, 2009 12:19:13 GMT -5
I have tumbled fluorite......you just have to watch it close.
Shannon
|
|
|
|
Post by rocklicker on May 15, 2009 12:23:04 GMT -5
As said, tumbling them together would not work. The fluorite would grind down too fast. It might provide a good filler for the obsidian if that's all you are after, but don't expect the fluorite to take a polish.
I've tried tumbling fluorite by itself and it never really took a polish for me. The rocks hitting together caused a dull finish no matter how much pellets I used. I ended up finishing them up on a polishing wheel. I did about 4 days in 120/240 then I checked in every day until they looked good. Then I went to 600 for a week, then tripoli prepolish (which I understand now was unnecessary) then finished them up by hand on a polishing wheel.
Steve
|
|
thomtap
starting to spend too much on rocks
Member since December 2007
Posts: 237
|
Post by thomtap on May 15, 2009 15:19:54 GMT -5
Well I think I'll give it a try. I have a vibrating tumbler, and I could start with a finer grit. I thought obsidian was a 5 or so on the hardness scale... is it really a 7?
|
|
|
|
Post by 150FromFundy on May 17, 2009 20:49:20 GMT -5
I still say Obsidian is a 5 on Mohs, as is commercial glass.
Agate or Jasper that are a 7 on Mohs will both scratch Obsidian and commercial glass, so the Obsidian is definately softer than a 7.
From what little I know about tumbling, Obsidian should be treated like Appache Tears. Omit the first coarse grit stage (60/90) and add an additional pre-polish stage (1000F).
150FromFundy
|
|
|
|
Post by 150FromFundy on May 19, 2009 6:27:23 GMT -5
The Rock Shed now sells Flourite and claims that it can be polished. They also post some pictures finished in an UltraVibe.
You have to do it as a load on its own. Omit the course grit stage (60/90) and start with the (120/240). Add an additional stage (1000F) beofre the polish. Check outn their site for additional tips.
150FromFundy
|
|
|
|
Post by johnjsgems on May 19, 2009 8:07:56 GMT -5
Obsidian hardness can vary a little but 5 sounds about right. Apache tears are also obsidian.
|
|
|
|
Post by MyNewHobby on May 19, 2009 15:11:16 GMT -5
I have a chunk of Mahogany Obsidian I got as a gift and am wondering as well on how to handle it.
Some say it should not be tumbled with anything else and also should have decent cushion.
As always...
Julie
|
|
Nov 15, 2024 17:44:51 GMT -5
Nov 15, 2024 17:44:51 GMT -5
