Question about a weird rock I found near the old quarry in Springfield

I was out walking my dog near the old limestone quarry in Springfield last weekend. My dog started digging at the base of a big pile of tailings and uncovered this rock that looked like it had little green crystals all through it. At first I thought it was just some slag or something, but when I got it home and washed it off, the crystals were really clear. I took a picture and showed it to my friend who works at the community college. He said it looked like olivine in basalt, which is weird because that quarry is all sedimentary rock. He thinks maybe a glacier dropped it there during the last ice age, like 10,000 years ago. I never really thought about how rocks can travel so far from where they formed. It makes me look at every loose rock in a field differently now. Has anyone else found a rock that just didn't belong where it was?

2 comments

2 Comments

dakota4791d ago

Found a chunk of granite in my backyard once, full of pink feldspar. The whole county is clay and sandstone, so how did it get there? Makes you wonder what's just under your feet.

nathanl361d ago

That's the kind of thing that keeps me up at night. Could be a glacial erratic, just a rock that got picked up and dropped by ice ages ago. But honestly, maybe someone's grandpa brought it back as a souvenir from a trip and it just got tossed in the garden. Weird how the simplest answer is often a person moving something. Makes you look at every odd rock in a whole new way.