Do you know this rock?

It looks to be 2 types of rock.
One being crystal (possibly quartz?) and the other...?
I have no clue.

the crystal seems to be holding the entire rock together.

No, I haven't tried a chisel... only a hammer.
Guess it wouldn't hurt to try (Some other day though, when my neighbors aren't home)

I second the vote for granite. Very coarse grained too. The white/clear grains are quartz, the pink ones are orthoclase (a feldspar). Should probably also be some dark/shiny biotite mica in there too, but I can't tell from the pic. If there is noticeale mica in it, that might cause problems for tumbling, particulary in a coarse-grained granite, since the mica tends to "flake" away. Otherwise, could tumble up nicely. Orthoclase is 6 on Mohs hardness scale, and quartz is 7, but I think that shouldn't be a serious problem for tumbling.

Thanks rollingstone and Silverfoxx and Cher for letting me know at least one of the types of rocks we have here in the river.
I should post up some other ones to see if anyone can identify them.

I haven't been able to to smash this rock with a hammer. Not even the smaller one (where you can see the insides).

From the small piece. I see no Micra at all. What you see in the picture, is exactly what I see physically. It may be different in the core though.

I'll keep trying to smash them to make them suitable size for tumbling. wish me luck
Alice

So sayith James.
So let it be written.
Really.
;D
It is some cool looking granite, I must say. I'd like to see what that does.

cookie

that is a pretty cool rock alice i seen ron (michiganrocks) post some of that befor i bet he tumbled some too you should ask him about it or maybe go to his web site and see if he posted a pic ---but i bet if it stays together it will grind flat and look good just let it go long in 60/90---------- heres his site

iavbbs.com/nichols/index.html

I guess I always pictured granite as being black, because of all the counter tops I've seen.
Guess they come in all sorts of colors.

Thanks everyone for your input.

The first rock is much too big to tumble in my 3 pound barrel. It won't even fit through the mouth. The smaller one fits, but seems a lot bigger then what I'm used to tumbling. It's about (without using a ruler) 2" X 3" X 1" thick.

Thanks Sands for Ron's link, I'll take a peek later on today.

I'll post up some more of out river rock when I have the time

Tweetie, you should come over to Ile Perrot with the kids, to go rock picking. We'd have a field day.

Hey Alice
You said you're having trouble breaking the rock with a hammer. Well, you know the old saying, use a bigger hammer. I use a regular nailing hammer and chisle to break stones that have cracks and fissures by placing the chisle on a seam.

Sometimes you have to kick it up a notch when the rock gets tough. Then I use a 3-pound hammer. I cover the rock with an old T-shirt and sock it with the heavy dude. It breaks the rock but you get a lot of slivered pieces. That's when I think it might be better to cut the rock with a saw into managable pieces that would tumble better than the slivers that I get after whamming with the 3-pounder. SilverFoxx.