Question about a rock!

[mummytrol]

Hello, dear friends! 6 months ago found a very heavy rock with a metal detector. It was 1 peace. Now it is cracked and falling apart. Maybe somebody has any idea what is that? The stone was stinking and had like silver metal surfaces. I cleaned one side of stone from inside for better view. The stone is very low magnetic, very strong magnet not sticking to it, just feeling a little puling!

 

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[vpnavy]

Welcome aboard mummytrol! It might help if you provide the location, etc. of your find...

 

[Jim in Idaho]

Looks like some kind of igneous rock, probably with some iron in it. The dark gray around the lighter center is probably where there was a crack that allowed water and oxygen into the stone and partially oxidized it. The lighter center is the natural color. Looks like some sort of basalt to me. Maybe an iron sulphide.
Jim

 

[mummytrol]

Welcome aboard mummytrol! It might help if you provide the location, etc. of your find...

The stone is from Coney Island beach(Brooklyn). Center of the stone is a metal. I think it is iron( we tested it- Fe Iron 794.5k
Mn Manganese 190.6k
Cu Copper 5987
Co Cobalt 4733
Ti Titanium 1258
Ni Nickel 607
Zr Zirconium 302
Nb Niobium 323
Hg Mercury 163
Sb Antimony 79) it is 1/million parts. So about 80% is iron.
Thanks for your answers! Mummytrol!

 

[Jim in Idaho]

I would think, with that iron percentage, it would be much more susceptible to the magnet. Sure has a lot of metal.
Jim

 

[Eu_citzen]

Rub it against a unglazed piece of porcelain. If you get a brownish streak - limonite.
If not: Pyrrhotite is also a possibility.

 

[DDancer]

Most likely a massive piece of Arsenopyrite. The red color is the iron oxide created as the material degrades. Pyrites cleave pretty easily and can fracture due to temperature fluctuations. That piece has been in the weather for a while so its probably developed a lot of fracturing~ so it'll kinda fall apart for a while. As to magnetics~ pyrites typically are not magnetic or are very weakly magnetic and can sound off on a metal detector.

 

[mummytrol]

Most likely a massive piece of Arsenopyrite. The red color is the iron oxide created as the material degrades. Pyrites cleave pretty easily and can fracture due to temperature fluctuations. That piece has been in the weather for a while so its probably developed a lot of fracturing~ so it'll kinda fall apart for a while. As to magnetics~ pyrites typically are not magnetic or are very weakly magnetic and can sound off on a metal detector.

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Thanks for you answers guys! Tried porcelain- does not work. What do you think about a smell of a stone, and its weight? its 4 pounds, I think more then the same piece of steel! Thank you for your answers again. Mummytrol!

 

[JLeonhardy]

Looks like decomposed slag to me. If it's a sulphury (rotten egg) tainted smell, likely sulphides gassing off a chunk of old lead smelting. Barges would sometimes use it for ballast in the early twentieth century.

 

[DDancer]

Arsenopyrite has a rotten egg smell when struck apparently.... check out Arsenopyrite - Wikipedia, the free encyclopedia

Checked it out when you said it smelled. I would expect it to smell as it degrades~ you say its falling apart~ if what Wiki says is true.
Sulfur is pretty strong stuff