Found a strange rock

Originally posted by Juston
Just found this outside my office. Pretty cool looking and really shiny, but kinda dull at the same time. Took the following pictures with my phone, but they really dont do it justice.
The rock itself feels really light.
Anyone know what it is?

It looks like Galena like someone else suggests, but that is a heavy mineral and typically cubical and much shinier and more grey and not black like you mention, but if its light it might be graphite, but to be sure we need you to rub it on some paper. Very cool looking rock, I would have picked it up too

This almost looks like a meteorite www.star-bits.com... but I'd suggest taking it to a geologist in your area to see. I'd love to know what you find out it is ^_^

Originally posted by mytheroy
I'm going to go with carbon, I found the same looking rock(s) while digging in a my dirt floor crawl space, really light, black dull and shiny

Yup...looks like a dirty piece of anthracite to me...coal.

Not knowing much about geology but am interested, can someone tell me why this would not be or could not be a black agate?

I hear they have a clearly discernible diffusion banding characteristic and am curious to know if this could be a charcteristic of this particular stone?

reply to post by catt3

catt3 please note that I was responding and replying to Juston the OP not to you.

reply to post by Juston


To me, iit ooks like a slightly dirty chunk of aluminum from the photo. Hematitie would be heavy as would be galena (lead). Lapis is not metalic, it's a mineral. Graphite is light but can be ruled out by rubbing it against a piece of paper -- if there is no streak left on the paper it's not graphite.

Originally posted by Juston
Just found this outside my office. Pretty cool looking and really shiny, but kinda dull at the same time. Took the following pictures with my phone, but they really dont do it justice.

The rock itself feels really light.


Anyone know what it is?

I propose this solution.


1)
Take a measuring cup fill it with enough water to cover the stone.

2)
Drop the stone into the water and see how much it has risen. The difference is the size of the stone.

3)
Weigh the stone on a kitchen scale. The weight divided by its size is it's density.


When we know its density, establishing its type should be a fairly straightforward process, and given that we also know how it looks, we can weed out the obvious incorrect candidates, so the measurements doesn't have to be super exact to be useful.


This ought to work, I think.

reply to post by Juston


If it feels really light
perhaps it is a PAPER MACHIE rock??? like they use in Hollywood props & stage props in school plays.

But after seeing this pic i838.photobucket.com... I realise it's not a rock at all, more like a large pebble that has the looks and feel of a rock.

OK I have contributed NOTHING useful to your thread

I have a minor in Geology, and it looks like coal to me. Flake off a small piece and crush it to dust, then see if it will burn. It is not obsidian if it is light, obsidian is volcanic glass and is relatively heavy.

reply to post by RocksFromSpace


I don't have a camera worth a damn, does anyone know where to send a slice to get it Identified?

I'll go with the guys saying graphite or coal, but make it anthracite in order to be specific.

en.wikipedia.org...