Baseball Magnets
Author: Baseball Bob
Mystery Rock???
Hello everyone, I am looking for some help with a stone I have had in my posession for quite some time.
Here is some background on it. I found this about 13 years ago while working for a man on his farm in the small Tennessee community of Hot Rock. It was underneath some ground I was turning (maybe about 6 inches deep).
The stone is almost perfectly spherical, about the size of a baseball. It seems extremely dense for it’s size. It weighs around 5-6 lbs. I have tried breaking it open and sawing it in half. All I managed to do was ruin a perfectly good saw, ripped the teeth right off of it and barely scratched the stone.
I have tried numerous magnets of varying power, none will stick to it or even pull on it.
Here are 2 pics of it, best quality I could get with my camera. .
http://a389.ac-images.myspacecdn.com/images01/56/l_ebcaa5140296e46de0cbb7e24b06bab4.jpg
http://a787.ac-images.myspacecdn.com/images01/64/l_69d2980784ed978a3ed2dc8bd053b0f2.jpg
It is not a meteorite, nor a cropolite.
One of the most important features here is the euhedral shape of the crystals in the surface and the size of them. Since it is very dense it is certainly either a sulfide or an iron oxide.
Pyrite (FeS2) is the most likely candidate, based on your description.
Another possibility is sphalerite, ZnS, but that is hard to tell with just the picture.
http://www.webmineral.com/data/Sphalerite.shtml
the color of sphalerite varies considerably depending on the iron content (that substitutes the Zn).
Is it completely opaque? or is it slightly translucent (light can go through it?)
If you want to cut it in half, you need to use a diamond saw or similar. If you go to a university with a geology program they can cut it for you. They can also help you figure what mineral it really is.
Another possibility is oxidized magnetite but it should have a reddish coating and still have some magnetism remaining, so it less likely.
So, go to a university with your rock. It is a cool specimen indeed.
2009 O-PEE-CHEE Baseball & VINTAGE MAGNET MAILDAY!