November 3, 2011

Mystery Rock #4

Posted by Evelyn Mervine

Mystery Rock #4, Photo 1.

Time for another mystery rock! This one was sent to me by Jess back in July. Jess, I’m sorry this took me so long to post. I blame my thesis… and wedding busyness… and also the fact that this rock actually has me stumped. I’m afraid that I can’t provide too much more insight into what this rock might be, other than that I think it’s sedimentary. Not very helpful, I know. I’m hoping that other geologists in the geoblogosphere can provide some more useful insight.

Here’s Jess’s original message to me:

Hello Evelyn!

I would SO appreciate your expertise in figuring out what kind of rock I have. My husband and I just recently took a trip to Traverse City, MI, and I found this rock about a mile from the shore in Lake Michigan. We took it to a few rock shops, and one owner said he had only seen a couple in the past, and that is was a jasper-hematite “blend”. He also said that one man brought one in, wanting to find out if he could tumble it, and because it is so hard, the shop owner told him it would take about 9 months to tumble. The man cut his rock in half with a wet-saw, which reportedly took about 6 hrs. to cut all the way through. The pattern on the outside is apparently the same throughout the rock. I’m barely able to scratch it with a roofer’s nail, and despite thorough cleanings it still smells faintly of sulfur (?). If there are any other details you need, please let me know! I would LOVE to know what this rock is, if you could help me out. Rock-hounding is an absolute passion of mine… determining what it is I’ve found is half the fun for me, but this time I’m stumped! Thank you either way:)


Well, I’m stumped, too, Jess! Hopefully some other geologists can help us out.

Here are several more pictures of the mystery rock:

Mystery Rock #4, Photo 2.

Mystery Rock #4, Photo 3.

Mystery Rock #4, Picture 4.

Mystery Rock #4, Photo 5.

Mystery Rock #4, Photo 6.

Mystery Rock #4, Photo 7.

Mystery Rock #4, Photo 8.

Any ideas, anyone?


More Mystery Rocks:

Mystery Rock #1

Mystery Rock #2

Mystery Rock #3