Any Rock Experts Here?

[redhawker]

Not being an geologist I"m not sure what this is but I thought it might be worth something so if anyone here has more knowledge then I about rocks maybe you can ID it and tell me if its worth any money or just a large paperweight. I've always meant to check this out but never got around to it and then, after a while, I forgot we had it in our back yard as it was in our tortoise "compound" and it was pretty much buried for at least 10 year, probably more. We recently sent the tortoise to a reptile rescue to get a new home as the kid's is grown, married and moved out and I really don't need a tortoise to care for. (figured some kid might appreciate it more). The rock has obviously been sliced flat on each end by a rock saw (why, I don't know) and the exposed rock at the cuts on each end are a dark green color. I'm thinking that it must be worth something other wise why would someone bother to saw the ends off of it? Could it possibly be a big hunk of jade? (could I be that lucky, LOL). The rock is about 7"x 7" x 5" and its wet in the pictures because I just washed all the dirt off of it. It has several, lets call them divots (courtesy of my son more then likely), on each end where it looks like "someone" pounded on it with a hammer.





Anyway, I'd appreciate any info you geologists might be able to impart. Thanks in advance.

 

[Chuckbuster]

"Wyoming Jade" maybe?
Used to be a bar in Medicine Bow that the bar top was made of the stuff. Owner found a Boulder of the stuff on his ranch outside town if I remember correctly.

 

[GunnyGene]

Well, it's igneous (volcanic), but without knowing where it originated and/or a lab analysis it's hard to know. Could be obsidian, which would be my first guess.

 

[wheelgun1958]

Could be obsidian, which would be my first guess.

My guess also. Particularly the way it's chipped on the edges. Chipped carefully, it would make a very sharp knife blade.

 

[Kevin]

BMFR.

It isn't jade. Jade is more traslucent. Igneous for sure. Perhaps some sort of serpentine?

It's kind of hard to tell from your pictures since the rock is in the shade. If someone says marble. Apparently "marble" is a Catch all term for many different rocks.

Bmfr....big....m.f. rock....

 

[sfhogman]

I was gonna say serpentine. There's lots of it in California, for sure.

 

[GunnyGene]

Could be obsidian, which would be my first guess.

My guess also. Particularly the way it's chipped on the edges. Chipped carefully, it would make a very sharp knife blade.

Sharper than any steel or other metal can ever be. About 3 nanometers thick at the cutting edge on a good one. That's so thin that you can't tell where the cutting edge is without a good microscope.

 

[redhawker]

I have no knowledge of the source. I believe the prior owner of the house left it here which would be about 17 years ago.

 

[powder smoke]

Looks like Granite to me, Granite comes in lots of colors and make ups depending on where it comes from. ps

 

[toysoldier]

"If I don't know what it is, I take it for granite." Just a little geology humor. :wink:

Not granite, which is composed of various mineral crystals that form as magma cools. I too vote for obsidian, a glassy rock that forms when magma cools too quickly for crystal formation. Might change my mind if I saw it in person.

Wheelgun, good point about the chipping. Conchoidal fracture occurs with obsidion.

 

[BearBio]

When I started grad school, we had an introductory class in different scientific techniques. One was electron-microscopy where we made slides for electron microscopes (both TEM and SEM for you scientific types). We made our scalpels from glass (same thing basically as obsidian).

You're in O.C.==take it over to Citrus College or Cal State Fullerton or LBCC and have a geologist take a look.

 

[Salmoneye]

Black Chert

 

[sfhogman]

Well, when you find out, please let us know!
In the meantime, I'm goin' for serpentine, California's State Rock!

So there.

Jeff

 

[6gun]

I'm not rock expert but I'd have to say what you got there is a paper weight.

 

[Bull Barrel]

Its a....rock.
Yep, take it to one of the local university geologists.

 

[JonFTC]

That looks cool. I come across lots of interesting rocks/gems when I go Rock Hounding and Gold Prospecting in the South Central Rocky Mountains here in Colorado. Usually when I find something like that which I'm unsure of, I go to the Geology professor at the University of Colorado in Boulder and show it to him and he identifies what I have found. I've found some interesting rocks. One of my favorite finds was a 6 lb chunk of Iron Pyrite.