osuguy0301
starting to spend too much on rocks
Member since December 2015
Posts: 203
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Post by osuguy0301 on Oct 22, 2016 6:26:07 GMT -5
I have a small box of rocks that have been sorted out as too soft to run with my agates, jaspers, quartz, and pet wood. It is mainly stuff that I got from mixed bags and have sorted out.
First, does anyone know the hardness of green opal? Its an olive green color and looks kinda waxy when rough. I did a search online but could find anything definitive. I think it is sub 6 because I think when i first got it I scratched it with a knife, not 100% though.
I have a number of small pieces of Labradorite. Its hardness is 6-6.5. Would that be alright to run with 7 hardness items? I am pretty sure I have ran some before and they rounded fine but didn't polish very well and had a hazy to them. Any suggestions on this?
I also have a fair amount of Septarian and Blue Apatite. Being that these are softer stones, is there anything special I need to do when tumbling them. Do I need to add a 1000 grit phase?
I also have some stones that are black with silver colored inclusions? They are pretty cool looking stones but they seem to grind really fast and when polished the silver looks shiny but the black is dull and scratched. I have no idea what stones they are, so any ideas would be great. They kind of look like granite but I don't know if that is it or not.
Thanks in advance,
Jake
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Post by Peruano on Oct 22, 2016 7:50:25 GMT -5
It sounds like you are asking too much of tumbling. Neither the opal or the labradorite would be polished by tumbling in my inexpert hands. Both too soft unless you want to develop a whole new technique. I know some soft stuff can be polished with dry media (ground up corncobs) carrying the grits was used for example. But that process might require you to have a lot of stones of same type and a vibratory tumbler.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,562
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Post by jamesp on Oct 22, 2016 9:57:34 GMT -5
When it comes to tumbling stick to hard if starting out.. Mohs 7-agate jasper pet wood.
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Post by vegasjames on Oct 22, 2016 13:31:29 GMT -5
The reason you probably cannot get a definitive hardness on the opal is because there are hundreds of different types of opal and hardness can vary in opal. Opal is not always just silicon dioxide. It can also contain varying amounts of aluminum oxide. The higher the aluminum oxide content the harder the opal.
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osuguy0301
starting to spend too much on rocks
Member since December 2015
Posts: 203
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Post by osuguy0301 on Oct 22, 2016 15:48:08 GMT -5
I never bought any of this stuff specifically, it all came as part of "mixed" rock bags from various places. If they won't tumble its not a big deal, its too small to do anything else with so I will just keep it as rough for the kids to look at or throw it in the flower garden.
Thanks, Jake
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Post by greig on Oct 24, 2016 12:17:55 GMT -5
I have had some success shining soft rocks in a rotary tumbler using just walnut shell dry. The bag I am using came from a pet food store and sold as natural cat litter. There is probably better stuff out there. I am still playing with it to see what I can learn.
As for the black rock with silver colored inclusions: You sure you are not looking at actual black rock with silver vein? I have rocks from Cobalt Ontario that look like that. Once they are exposed to air for a while, the silver shiny stuff will stay shiny (if silver) or fairly quickly turn copper colored (if nickeline).
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