Which of these various rocks can safely be tumbled together?
Dec 15, 2022 19:22:20 GMT -5
rockjunquie and dshanpnw like this
Post by misakamikoto on Dec 15, 2022 19:22:20 GMT -5
After tumbling for about a year using rocks our family has collected around our area and while on hiking trips, we got some tumbling rough for the kids for Christmas so we can all branch out and tumble some things we’ll never see around here.
I’ve looked up the Mohs hardnesses of the various stones to get an idea of what rocks we can mix in the tumblers (Lortone 3A and QT12, running SC 60/90, 120/220; AO 500, 10,000), but I’m still unsure about a few types, whether because they’re a special case or because various sources conflicted on their hardness.
Here’s what we have (purchased from Gems by Mail, Meeko’s Mine, and The Gem Shop, although unfortunately most of the listings didn’t give Mohs data), separated into groups I’m thinking can be tumbled together?
(I did also read that obsidian should be tumbled separately even from other stones of similar hardness, so we’ll be doing that for sure.)
Thanks for any pointers anyone can give—I know a lot more than I did a year ago, but I’ve still got quite a bit to learn.
I’ve looked up the Mohs hardnesses of the various stones to get an idea of what rocks we can mix in the tumblers (Lortone 3A and QT12, running SC 60/90, 120/220; AO 500, 10,000), but I’m still unsure about a few types, whether because they’re a special case or because various sources conflicted on their hardness.
Here’s what we have (purchased from Gems by Mail, Meeko’s Mine, and The Gem Shop, although unfortunately most of the listings didn’t give Mohs data), separated into groups I’m thinking can be tumbled together?
Batch A | |
2–2.5 | amber |
Batch B | |
2–4 & 5-6 | chrysocolla & turquoise |
Batch C | |
3 | calcite |
3.5–4 | septarian |
Batch D | |
4 | fluorite |
5 | apatite |
Batch E | |
5–5.5 | Apache tears |
Batch F | |
5.5–6 | sodalite |
Batch G | |
5.5–6.5 | hematite |
Batch H | |
6–7 | labradorite |
unakite | |
Batch I | |
6.5–7 | jasper (blue swirl, blue chalcedony, coconut, dragon’s blood, kambaba, leopardskin, mooka, polychrome, rainforest) |
tiger’s eye / hawk’s eye | |
Batch J | |
7 | agate (Bahia, carnelian, green tree, Swazi rose) |
amethyst | |
aventurine | |
Batch K | |
7–8 | dumortierite |
petrified wood |
- Is this anything like how we should be grouping them for tumbling?
- I’m particularly uncertain about the chrysocolla/turquoise meld, which mixes two very different hardnesses within a single stone. How should I treat this stone?
- I’m seeing conflicting information on the hardness of tiger’s/hawk’s eye (some said as low as 5.5), although most sources seem to say about 7. Is that correct?
- I did read that fluorite and apatite can be tumbled together, but seeing a whole point of hardness (although I realize the scale isn’t linear) separating them makes me nervous. Are these okay to tumble together?
- Septarian contains calcite, but is the rest of the rock too hard to tumble with calcite?
- From what I’ve read, a lot of things that are called jasper aren’t quite as hard as true jasper and thus may be appreciably softer than agate to the point that they may need tumbling separately. Better to separate jaspers and agates to be safe?
- Although we’ve been tumbling for about a year, we are tumbling novices. For example, I haven’t been checking Mohs hardnesses until lately, and it was only quite recently that I discovered the importance of using AO for the prepolish stage as well; and we’ve just now switched all the way up to 10,000 for the final stage. And in fact it was only today that I saw this subreddit’s FAQ example of an (apparently) smooth lake stone before and after the grit stage—having just run a couple batches of (apparently) smooth lake stones myself while skipping the 60/90 stage. So I’m learning, but I’m not an expert. That being the case, are there any things in this list, whether particularly soft or hard stone or just plain tricky types of rock, that we should wait on tumbling until we’ve had a little more experience?
- From what I’ve been reading, instructions provided by tumbler companies often call for more medium than is actually needed. People who are using the QT3 and QT12, how much do you use for the various stages? I’ve been going by Lortone’s book, but I don’t really know how to judge whether I’m using too much.
- Is it better not to tumble sodalite and hematite together even though they have a similar hardness? I wasn’t sure whether the metal content of hematite would screw with the process in combination with other stones.
- Finally, can I tumble all stones of the same general type together, or are there meaningful variations in hardness among subtypes? (Specifically I’m wondering about the agates and the jaspers.)
(I did also read that obsidian should be tumbled separately even from other stones of similar hardness, so we’ll be doing that for sure.)
Thanks for any pointers anyone can give—I know a lot more than I did a year ago, but I’ve still got quite a bit to learn.