Ideas for the Rocks that are more Brittle

[NevadaBill]

I have a bunch of rocks which are (I believe) stained Quartz. 

But, even though the rock which created the stain (a green rock) was very brittle, and soft, the host rock (I believe Quartz) is ALSO more brittle than regular Quartz.  I think.

So, this bucket load of rocks, which I thought I was going to have to use a trim saw to reduce, actually broke up with much less effort using a 4 lb. hammer and good chisel. 



Now, I have rendered down a lot of this load in to about enough rocks to start a 6 lb. or 12. tumble.  But I am kind of worried they might get broken down to little crumbles, and not take a shape at all.

Without having them in front of you, anyone with experience tumbling (6.5 ish hardness, brittle) rocks could advise me:

A)  Should I tumble them all by themselves in Stage 1?

I am thinking that the less brittle Agates and Jaspers might annihilate these guys

B)  Should I buy some Plastic Pellets and use those instead of Ceramic?

I am thinking that Ceramic is harder than the stone, and might break the brittle Quartz up, rather than shape it.

C)  Should I start with an AO 80, or SiC 80 grit, rather than hit them with the 46/70 SiC grit I plan to??

Sorry, full of questions here.

Note:  I don't have the patience to watch my Vibe try to shape these rocks for 45 days, so I am using a Rotary tumbler on them.

or 

D)  Just chuck them in there with the Agates and Jaspers you wimp!  Come on!

A lot of the smaller ones look like this (more solid), and have good color:



But I'm afraid for them.

Thanks in advance to any of the Pros, who knows!

[arghvark]

That's some really neeto material! If it was me, I'd try a couple of experiments. Maybe put a handful in with a batch of hard stuff, check after a few days? Do the same with a batch of softer stuff?

You got a fair amount, could also just do a homogeneous batch. Smaller barrels will be kinder and gentler.

[jimaz]

I’ve got a load of similar looking material currently running first stage in my 45C using 60/90 SIC. About 50-60% small aquarium gravel for cushioning and a little extra water. Checked after five days and only had one rock that fell apart, some decent shaping on the other rocks. I was surprised that the slurry was not very thick, very gritty from the removed material. I did not add anything to thicken the slurry to start as I thought it would become thicknquickly on its own. I recharged with some slurry from an earlier load that was not completely broken down and added a little more grit. First time with this material, but happy so far.

[NevadaBill]

Arghvark ~ Good idea. I have enough to do an experiment like this actually. It is not valuable rock really. I'll put some aside to throw in with the next Stage 1 cycle to see what happens to them after a week.

Jimaz ~ Those are some great points! I didn't consider using 50-60% media with the load, or using extra water. I also thought about thickening agents (makes sense to me) too. I am going to run these rocks independently first try, and implement these ideas exactly.

In case you circle back to this thread, I have a question. Could you describe how exactly you can "recharge using some slurry from an earlier load, which has not been broken down"? Do you keep some slurry around? I have never thought about this.

I realize the idea of tumbling brittle rocks might seem like a pretty trivial subject for some, but these are exactly the kinds of tips I was hoping the collective experience of the RTH community would take their time to share with me.

Thank you!

[jimaz]

I don’t normally keep slurry bit had a load that I pulled early because the lid was leaking. The load had not ran long enough to completely break down the grit. I pulled out the rocks by hand and then poured the slurry into a large disposable food storage container, let the solids settle and then poured off the water. There was a lot of grit left. I know a few of the board members save the slurry from stage one as a starter/thickener. I used a putty knife to scrape up the sludge from the container and added it to my tumbler barrel and then rinsed remainder with water to add liquid to the barrel. I also added a couple more tablespoons of grit.

I’ve never done this before, just gleaning knowledge from others on the board. I did run a couple of pieces of this material in a regular load that came out OK. A little different looking and did not shape well. I’ll try to get a picture and post later today.

P.S.  I’m not a pro by any means.  Only beeen tumbling a few months and still learning.  I figure the best way to learn is by experimenting on occasion.  Learned a lot from reading the forum.

[rockjunquie]

Mar 24, 2019 10:13:49 GMT -5 NevadaBill said:

Arghvark ~ Good idea. I have enough to do an experiment like this actually. It is not valuable rock really. I'll put some aside to throw in with the next Stage 1 cycle to see what happens to them after a week.

Jimaz ~ Those are some great points! I didn't consider using 50-60% media with the load, or using extra water. I also thought about thickening agents (makes sense to me) too. I am going to run these rocks independently first try, and implement these ideas exactly.

In case you circle back to this thread, I have a question. Could you describe how exactly you can "recharge using some slurry from an earlier load, which has not been broken down"? Do you keep some slurry around? I have never thought about this.

I realize the idea of tumbling brittle rocks might seem like a pretty trivial subject for some, but these are exactly the kinds of tips I was hoping the collective experience of the RTH community would take their time to share with me.

Thank you!

In case you didn't know already- you can tag someone to get their interest or ask a question by putting the @ symbol in front of their screen name without a space. 

[hummingbirdstones2]

Some of the rough in the second photo looks a lot like some low-grade silver ore that came from an old miner down here in AZ. Silver sulfides in low concentrations look gray in quartz.

Sorry - can't help with the tumbling.

[jimaz]

Here are a couple of pictures. The stone is a little bigger than a dime. Lost about 3/4 it's size in tumbling.





One more from a similar material, also a little bigger than a dime.


There is a wash across the street from my house that runs 4 to 5 times a year where i like to search for stones. It's about 2 mile downstream from the tailings pile from two different copper mines. Photo is not that good, but you can see the tailings of one of the mines on the horizon.

[hummingbirdstones2]

Yep - copper mine would explain the appearance. It's cool you have tailings like that close enough to get to easily.

[NevadaBill]

Copper mine is a very good guess. There a few of them within an hour of the area I found these. And RTH member VegasJames also identified this as being a strong possibility.

I have found some very blue Azurite looking material, and some Chrysocolla / Malachite looking material too. I don't have enough to make any jewelry, but I can tell you that it is both soft and very brittle.   I am kind of afraid to tumble it.

The Quartz looking stuff appeared more stable.  It just shatters a bit easier than regular Quartz.

The pictures posted above look to me, like something I understand is called "undercutting". I could be wrong with that terminology. But that is what I am afraid of most when tumbling this stuff.

So, the pictures I took are of stuff I plan to put in the tumbler is going to be more stained Quartz looking.  I will stay away from tumbling any of the pieces which have more of the green or blue material on it.

I found a thread or two which shows some of the rocks (that have more green or blue in it) tumbled, and they looked very pretty, but they were done by experienced members here, and there was no discussion of technique.

Thank you for your time to show my those examples though. If mine turn out half as good, then I will probably post them.

[jimaz]

Definitely undercutting on the one stone. I didn’t go further because it was already pretty small. I’m looking forward to seeing the results of the current batch. The first clean out didn’t so a lot of signs of undercutting. Will know more in a week or so.

[NevadaBill]

Mar 24, 2019 11:28:05 GMT -5 rockjunquie said:

Mar 24, 2019 10:13:49 GMT -5 NevadaBill said:

Thank you!

In case you didn't know already- you can tag someone to get their interest or ask a question by putting the @ symbol in front of their screen name without a space. 

Thank you for sharing RJ.  I will definitely do so in the future when I want the RTH member to see the post.

[NevadaBill]

RTH member hummingbirdstones2 is right. You are lucky to have such nice material in your own back yard.

Update: Yesterday, I decided to sacrifice a handful of the smaller rocks, and put them in the Rotary tumbler with some of the other harder stones, ceramic media, and 46/70 grit SiC. We will see what become of them in a week. Fingers crossed. I'll post results.

[Fossilman]

I have tumbled some northern Nevada material, very similar...… I just tumbled it like any other material, but just buy it's self without other material..
It came out great....