Hey /r/askscience I've had this "rock" almost all of my life I've always wondered what it is

northern_redditor · 3 months

Mining engineer here with some geology background. This looks similar to the type of rocks found in a lead-zinc-silver mine that a colleague of mine previously worked at. Based off your images I would suspect it is galena, maybe sphalerite. Hoping a geologist can provide more insight.
Galena: http://mo.water.usgs.gov/projects/mining/images/Galena.jpg Sphalerite: http://crystal-cure.com/pics/sphalerite.jpg

I have a sample of a meteorite at my parents home. It looks similar to this: http://upload.wikimedia.org/wikipedia/commons/9/98/Old_Woman_Meteorite.JPG Which oddly resembles what a smelted ore would look like.

Hope this helps!

ShellfishGene · 3 months

Looks kinda like pyrite to me.

GeoManCam · 3 months

it looks like it might be refined ore of some sort, but you'll have much more luck posting in /r/geology. What country/state do you live in?

JarlBear · 3 months

Speaking as a 4th year geology student, I'd say it looks like arsenopyrite, could be Galena as well, its a bit hard to distinguish when so much light is being reflected off it. You can test it by scratching it with a penny, if you're not able to make marks its probably arsenopyrite. As someone who has worked intensively with meteorites I can say that, that is definitely not what it is.

TheWrongSolution · 3 months

It doesn't look like a meteorite to me. My bet is that it isn't magnetic, try holding a fridge magnet to it to confirm. The luster seems to me to be a sulfide mineral. You say it's dense so I see that it could be, as others said, galena. However it looks to me much too light in color. I would go with arsenopyrite. Here is one from my collection.

Edit: it seems that JarlBear has already posted my proposed answer.

clintonsclit4u · 3 months

laic here. if magnetic maybe elemental iron? then a meteorite is a possibility.

captainsmartypants · 3 months

Hi! could you weigh it, and also put it in some sort of fluid - water probably works - and calculate about how much fluid it displaces? That way someone clever could figure out density. I'm hoping someone more geologically inclined than me can use this to figure out something, the answers you've gotten seem like mostly guesswork so far :)

dwhipp · 3 months

Maybe I'm seeing things differently, but based on photo 2 it looks like it may be layered and micaceous. In photo 2, are there regions of darker, non-reflective rock with white-ish layers in between? Second, if you scratch one of the reflective areas with your fingernail, are you able to 'flake off' anything? Are those reflective bits flaky/platy? If so, you're looking at either a weathered white mica schist or gneiss, imo.

nomdeanon · 3 months

I'm going with pyrite as my first guess, especially if it has any yellowish / gold color to it. If it is more dull silvery color, then galena would be my second guess. If it feels nearly as heavy as a chunk of lead with a similar size would feel, then galena seems pretty likely.

One easy way to find out is to take it to your nearest geology department and ask around.

edit: could you try marking a piece of paper with it, does it leave a mark?

ka0ticstyle · 3 months

Pretty sure it is Iron Disulfide a.k.a Pyrite a.k.a "Fools Gold" - [http://en.wikipedia.org/wiki/File:Iron_disulfide_pyrite.jpg]

Used to have a bunch when I was younger. Pyrite

Payador · 3 months

"Fools Gold" I had one similar and this is what my Dad called it.

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