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Geology/rock identification

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Question
rock
rock  

 rock
rock  
I found this green, grey rock that has flow lines on it and is very smooth and is unlike any I have seen in my area.. Im in Woodstock ont. I found it out in the bush while hiking. My first though was it maybe a meteor stone. But because of its colour Im not sure. It doesnt seem to attract a magnet either. The flow lines and smoothness is what throws me off..can u please help. thank u.

Answer
Dear Mike, Goodmorning and Fraternal greetings!

While appreciating your interest on Rocks, my answer is given below.

It is very difficult to identify the rock by observing in the photograph, however with naked eye and also with the help of some physical properties of rock (only geologist by physical observation) it can be identified,
Probably this is a volcanic rock, with, Vesicular texture characterized by a rock being pitted with many cavities (known as vesicles) at its surface and inside. These vesicles form during the extrusion of magma to the surface; as the pressure decreases dissolved, magmatic gases are able to come out of solution, forming gas bubbles (the cavities) in the magma. When the magma is extruded as lava and cools, the lava solidifies around the gas bubbles, preserving them as vesicles.
This specimen is having a glassy coating, it's probably not a meteorite. I predict this is usually Basalt or Andesite which has cavities, or vesicles, that are filled with secondary minerals, such as quartz and chalcedony.


with regards
Dr. D S Subrahmanyam

Geology

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Dr D S Subrahmanyam

Expertise

All questions related to Geology, Geotechnical Engineering (especially in-situ stress, in-situ Deformability and Shear investigations) required for underground tunnels and excavations, Dimensional Stone Mining. Can't answer Soil dynamics related to Geotechnical Engineering

Experience

Geology and Geotechnical Engineering and Dimensional Stone Mining

Organizations
National Institute of Rock Mechanics (Govt of India)

Publications
International Journal of Mining Engineering and some other Indian journals

Education/Credentials
Doctorate in Geology

Awards and Honors
Reviewer for 3 International Journals

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