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Green Rock
Green Rock  
I have a rock that I bought but do not know the name of. It is shiny kind of mint colored and seems to be made up of chips of the stone. Thanks!

Hi Zoe,
The image you sent is pretty blurry but I can see some things in it that, with your description, make me sure you have a mineral called "asbestos".  You describe the rock as "mint colored", the end looks like it's "frayed" to me, and it also looks a bit bent.  All those things can be characteristic of asbestos.

It's a mineral that is made of, mostly, the element silica (most sand is silica) and many other elements such as Magnesium, Oxygen, and Hydrogen.  That would make it a "hydrated magnesium silicate".  There are six types of asbestos and they can be green, red, blue, yellow, and white in color.

It's made of thin, fibrous crystals so it looks like it has threads in it.  It's chemical makeup and physical structure give it good tensile strength, good sound absorption properties, and it's most important use; it is fire and heat resistant.  Because of those characteristics it used to be very popular with builders.

People have been using asbestos for 4,000 years, but we have recently found that those small, fibrous crystals can be breathed in and can cause lung diseases or cancer so it isn't used anymore for the purposes I've mentioned.  There are still a lot of uses for this mineral but there is a variety called Chrysotile that is more platy than fibrous and it is used extensively in the world.  As long as the fibers are contained, asbestos can be safe.  

The U.S. hasn't mined asbestos since 2009 but the largest producer is Russia.

Here's some pictures of asbestos, including some that look like yours; mineral-chiseled-from-the-earth.html

Here's a link to a United States Geological Survey mineral report on asbestos;

Hope this helps.


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C. Robert Reszka, Jr.


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.


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.

Michigan Basin Geological Society

Decade of North American Geology.
Bedrock Geology of Michigan

BS Wayne State University

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