Thread: Question for you rock hounds.

Originally Posted by thebigspendur

This is a pic of some purple quartzite found in the devils lake area of Wisconsin, unique stuff.

Ooh pretty stuff.

You have a college nearby? Contact the Geology Dept. They usually have a lab and true lapidary saw they might let you use.

Originally Posted by thebigspendur

You have a college nearby? Contact the Geology Dept. They usually have a lab and true lapidary saw they might let you use.

Yeah, That's a good idea. I was thinking about taking it over there anyway just so I can get a positive identification on it.

Once you get a big enough patch lapped flat you can do some testing to see if it's even worth going further. I've learned to pick up some small pieces of given layers for testing, (I know that you didn't have that option on this stone) The lapping time goes up exponentially with the area. SiC on a piece of granite is my preferred means of flattening. I try to start with naturally flat surfaces. High spots can be removed with a series of shallow saw cuts and then breaking or chiseling the leaves of stone between the cuts.

Good tips!
So, as requested here's some progress pictures.
Here is what the cutting wheel did after about 5 minutes or so.

Damn! I guess that's not going to work. So I switched to the grinding disc. Here's what it did after about 5 -10 minutes.
Double damn! So I switch to the belt sander. It worked much better but, as stated, it was a big dusty mess in the garage which I didn't stick with for more than a couple of minutes because of it. So then I went back to the manual work and so far this is what I have gotten.

So you can't really see how shiny it is in this picture but you can see on the top left and bottom right corners that have lapped out the color which is that beautiful kind of forest green. It kind of reminds me of that British Leyland British Racing Green. It's going to be a lot of work for sure to get this to be usable but I have a real good feeling about how this stone is going to turn out as a small natural stone.

Hard to tell from the pictures, but I'm thinking schist. I tried a few pieces of schist and my results were not worth a ...., but I have heard of schist being used for hones so some of it must be OK.

Good luck

I’ve cut a few rocks. I’ve also got some tile saws. Saying tile saw does not really define it. It looks really hard. You could try to split it. It looks volcanic. Which one it’s tough to say. I’ve made hones from volcanic rock. I’ve given up on that. Not that you can’t get good hones. They do take forever to lap. If there are granite counter shops around, you could ask them to cut it down. Then you still need to lap it. Under water works best. One of the very difficult things I have found in finding good rocks is having the matrix very consistent. Mostly I have been focusing on uniform slate and metamorphic rock, it is way easier to work with.

If you are going to be doing a lot of exploration for hones it might be convenient to get a vibrating lap machine. You just add water and some media like alumina or cerium oxide and let it run a few days and you have a nice mirror polish.

I see. That's a very intriguing proposition.

Edit: I saw one called Vibra Lap...that sounds like something you'd get at the nudey bar.

Well, the plates on the machines are interchangeable since once one is loaded with a certain grit or material you use another for a different material so I guess if you had a mind to you could fill one with some kinky material and have at it with your....censored....