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14,374 users

What rock is this?

0 votes

Thei found this on the beach. It doesn't burn so I am guessing it's not coal. Can anyone help?

Found at Raritan Bay in NJ. Weight is 30g. About 1.5" long. Little less than .75 high. Doesn't seem to be magnetic.

asked Aug 23, 2015 by Xylina35 (120 points)
edited Aug 24, 2015 by Xylina35

2 Answers

0 votes
Maybe flint. Maybe not. Where on the beach? Jersey, California, the Great Lakes. There is a lot you can do to help us. Is it magnetic, is it heavy for its size, does the rock feel waxy where the conchoidal fractures are? Heck it could be silver, tarnished everywhere but where it fractured.
answered Aug 23, 2015 by Weasel (52,270 points)
edited Aug 23, 2015 by Weasel
Found it at Raritan bay in jersey. Weight is about 30g.
Does not appear to be magnetic. It's about 1.5 in long. A little less than 3/4in high.
I have more pictures if you are interested.
0 votes
It's color, shape and size remind me obsidian - "apache tears". But at the fourth photo (from top to down) it is probably not obsidian.
answered Aug 26, 2015 by Birthstones.eu (1,600 points)
Yes, I have to agree that it looks like obsidian, but there isn't any obsidian in the area of Raritan Bay. Unless its a glacial deposit from the moraine which is nearby that somehow deposited there - though that scenario is very unlikely. Based on its strong conchoidal fracture, waterworn glass would be my best guess. It doesn't look natural.

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