You are here:

Geology/Green rock

Advertisement


Question
Green rock
Green rock  
I found a few of these green stones. They have dark green to light green swirls to them. I don't know if these are the same because one is solid green the whole way through the rock and is flakey like flint rock. The other one has these pores in it that look like a normal rock inside of them. I have included a picture in hopes that we can finally figure out what these are. Thank you so much in advance.

Answer
Hi Nick,
Very nice specimens. You have examples of glass slag. It's basically rough glass from a blast furnace. This was probably from a glass making operation, although slag from an iron furnace can be very glassy.
It can have value as an antique since much was produced in the 19th century from iron smelting factories and from glass making facilities. It was used for commercial purposes and for lamps, and jewelry. I don't know how old your sample is or if there were any iron factories near the area. You might be able to find out more if you take it to a local university or rock club.

Here's a picture that looks much like yours.

http://www.forginglinks.net/2011/05/glass-and-iron/

Hope this helps.
Bob

Geology

All Answers


Answers by Expert:


Ask Experts

Volunteer


C. Robert Reszka, Jr.

Expertise

I can answer any general geology question (rocks, minerals, stratigraphy, geomorphology etc.). My expertise is in the geology of the Michigan Basin, PreCambrian, Paleozoic and Recent. I can answer questions concerning mining and petroleum exploration and production and the laws concerning those activities. I can also answer questions concerning stratigraphy of the Michigan Basin. I will also answer questions about mineral and rock collecting in the Basin. I won`t be able to answer many specific questions on hydrology, geophysics or geochemistry. I may be able to answer very general questions in those venues.

Experience

I have been working for the State of Michigan for 36 years as a Geologist and a Resource Analyst. I have experience with Subsurface Geology and Petroleum Geology, mining in Michigan, and Sand Dune Mining and Protection issues.

Organizations
Michigan Basin Geological Society

Publications
Decade of North American Geology.
Bedrock Geology of Michigan

Education/Credentials
BS Wayne State University

©2016 About.com. All rights reserved.