HI there, I found this "rock" about 25 years ago in Southern Minnesota... I have not been able to find out what it is... can anyone assist? It is very shiny, almost Chrome looking and extremely heavy.
Thanks
Chuckphoto (2).JPG
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HI there, I found this "rock" about 25 years ago in Southern Minnesota... I have not been able to find out what it is... can anyone assist? It is very shiny, almost Chrome looking and extremely heavy.
Thanks
Chuckphoto (2).JPG
Looks like blue pyrite...
It's years, or decades since I've done any mineralogy, but this evoked the response stibnite. If you draw it across a ceramic material it should leave a streak. Does it do so?
This link goes to a mineral table that might prove useful for your purposes. There are images of the minerals when you go to the home page of each.
Mineral Identification Key - Table IB
Its a large chuck of massive galena. The cleavage planes and metallic coloring are distinct.
does galena show such a blue colour ? i would have thought it was more greyish metallic
It's dependent of the amount of oxidation on the surface, and also the quality and type of light that is reflecting off the cleavage faces from the window in the background. Also note that the crystal structure is clearly cubic (isometric) so azurite and stibnite are eliminated. Whereas the clearly silver-blue metallic coloration and distinct cleavage planes of the crystal eliminates pyrite as an option.
0095554001350221181.jpg
note the isometric faces and blueish tinge dues to minute oxidation to smithsonite/hemimorphite on the faces. (Specimen can be viewed here http://www.mindat.org/photo-492604.html
fair enough, i relent in the face of your expertise - azurite was a mere layman's (and only slightly educated) guess, and i'm quite willing to amdit that i could be wrong
its all good
I'd say galena. You say it is highly metallic and dense, so if it breaks into cubes when crushed, it's most likely galena.
That's a nice big sample, too. Good find.
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