Thread: Question for you rock hounds.

So today I went to the house of one of my surfing buddies. He had a.stack of rocks I was admiring And I joked about that tendency that is a side effect of HAD where you look at random rocks and say, "Hey, I'll bet I could hone a razor on that."... Then I saw this one and actually did say that.


To which he replied that I should take it. At first I thought it was slate because it looked very gray in the shade but in the bright sun and looking at the little chips off of it...


...you can see that it is very green and has a very even sparkly mineral to it. I asked him if he knew where it was from and, as he is a bit of a hoarder, he said, "That might be from Alaska... Or from North Carolina. One of the two."
Sooo... I'm wondering if anybody has ideas of what it might be. I'm thinking maybe basalt from what I could see from pictures on the internet. It's very dense and very heavy for its size. I thought that I would smooth off that top side and lap it down. It also seems very hard and if nothing else it might be a good slurry stone.

Any ideas?

Edit: Oh, and also if you thought it might be good for honing.

It's not slate. Though slate comes in many colors it's usually in layers that are obvious and is very fine grained which that it not. Basalt is dark, very dark almost black.

With any rock unless it's you have a fresh surface weathering can make the outside look totally different than the inside.

From what you are saying sparkly and little chips fall off that could be mica falling off. It could be granite or many other things.

Well no chips falling off. It looks like it was chipped from hitting something. I do know that slate comes in many colors...I guess I didn't say that right. It's not the color so much that makes me think it's not slate. It's that it doesn't seem like it's layered.
I'm going to take the diamond wheel to the top of it then lap it on SIC and see what I get. I just wanted to post some pictures before it was cut to see if anybody had an idea.

I'll venture a guess at a quartzite.
If it is, it may make a good hone but will take some work to lap it.

I thought that might be it also and BOY are you right about taking a lot of work to lap. I figured I would "just" knock down the high spots with the cutting wheel or the grinding disc on the angle grinder. Yeah, well the angle grinder barely even touched it. The belt sander with the Al oxide belt did a little better but that makes an unpleasant mess so back to hand lapping on the diamond plate first. I have one I got in a lot of stones that I don't really use for much as it is too course. After that it will be back to the SIC plate. What is so far revealed though is a beautiful medium dark green and almost gem like smooth surface but opaque. Think of a yellow coticule except green and shinier. I can't wait to see how it turns out.

Please, post pics of your progress with it.
My quartzite cut fast with slurry from a diamond plate on one side and give a nice frosty bevel with oil on a well prepped and burnished other side.
If you're happy with it after lapping, you may want to find someone to cut it so you can use 2 sides. Double the lapping fun

I had actually thought about cutting it in half or possibly into three. I think three would be a little bit too thin though. I think that would take more than just a wet tile saw as hard as this thing is. Probably need to take it to a granite cutter I would imagine.

If it's quartzite that's metamorphosed sandstone and is tough stuff indeed. You need a proper saw to cut that stuff like a diamond saw.

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

I have a friend who has a tile saw but I'm afraid that this stone is just a little big for it. The wet tile saw will cut it I'm sure but it is usually used for tile which is normally 3/16 to1/4 inch thick and certainly always less than an inch. Maybe I'm wrong but I'm sort of thinking it would be like trying to cut a railroad tie on the table saw. You could do it but it's really pushing the boundaries.