Unidentified Metal- please help

Hello, I have been looking this up and cant figure out if its Magnesium, Silver, Aluminum, or something else (I know the chance that its silver is highly unlikely). I found these "rocks" in my orchard. The first thing I noticed when I went to move them was that they are extremely dense and about 5-6 times heavier than a regular rock of the same size. One piece is about 10"x12"x12" and weighs 52 lb. There is a small pile of these and they add up to about 200 lb, and there's only about 7 to 8 pieces.
But they look the same shape and color as typical grey/ black Oregon rocks, only slightly darker. A couple of them have formations on them that slightly resembles a meteorite type appearance or like volcano rock but without the holes on the side.
One of them had some shiny metallic like surface showing where a piece had chipped off. I knocked a couple together and saw that it was basically some sort of oxidation over the metal. It does not come off easily at all- You have to use something like a grinder to be really effective. When they knock together it sounds like iron hitting iron, but they're not magnetic at all.
They have the shiny pure metallic silver color through them entirely, not bits and pieces. And on the outside they are coated with oxidation and look like rocks. So they are chunks of something.
THEY ARE NOT MAGNETIC, so hey cant be iron. They spark when you repeatedly strike with a hammer. But I broke some small crumb like pieces off to try to light as magnesium would and it wouldn't. I also tried the Magnesium "Vinegar" test using white vinegar on a couple of the pieces where the metal was exposed and nothing happened.
So I don't know what this is. If anyone has any idea that could help it would be greatly appreciated, thank you!

i think you're likely going to hear, "photos, plz"

Ive uploaded some pics, links below. The camera didnt really pic up how shiny the insides are, and how dark the outer part is. But its basically as I stated above- they look like rocks on the outside and are shiny on the inside.

Here are links to pics I uploaded:
http://www.flickr.com/photos/76021178@N03/6974982745/

http://www.flickr.com/photos/76021178@N03/6974982079/

http://www.flickr.com/photos/76021178@N03/6974981613/

In the pics, the middle smaller rock has that different looking surface that looks like youd see in a volcano rock type thing

The magnet will not stick to it. I have a strong magnet here and it had no reaction at all. I havent tried a rare earth magnet though.

wow man, that is pretty wild, haven't seen anything like that either

Does anyone know a type of place where I could take a piece to get it tested for what it is?

you might should try a rock hound site, or maybe a university geology dept

You might be able to bring it to the yard and have them shoot it with the XRF gun. If they have one. That's pretty insane. Going to see if i can do some research on it right now.

... looks kind of like specular hematite, but that usually sticks to a magnet...

Theirs a show on TV about those space rocks. Dudes go around and find them space rocks with a magnet. That's what i thought you had, but then ya said they dont stick. So hmm.

Thats what I thought it was at first too, but it doesnt stick to a magnet and when i hit 2 pieces together i sounds like how cast iron sounds when you hit it, but the magnet sticks to iron.

Ya I'll probably do that.

That looks similiar, but Galena is 2.5 to 2.75 on the Mohs Hardness scale and this is atleast a 4.5 to 5. I cant scratch it with a knife blade unless I use alot of force or hit it with it, then it will leave a scratch. And there are no crystal structures on any of the "rocks" Ive found. I now all specimens of Galena probly wont have the crystal structure, but I have 7 to 8 good size pieces and they all look pretty much the same.