Is this rock Fulgurite

Scott11

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Nov 3, 2017
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I know nothing about rocks but found this on a beach in Ecuador 15 years ago. Someone I know saw it recently and said it was fulgurite. Just curious. Thanks! zIMG_9208.jpg
 

DDancer

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It does not appear to be a fulgurite to me. Fulgurite is formed when lightning strikes fuse the minerals in the ground into a glassy composite. They can take many forms and depending on the minerals involved and where they form can take on a variety of shapes and forms. A quick net search on images of fulgurites can show you this.
This is a fulgurite I found in the Western Australia outback while prospecting, I have several from my trips, sorry I did not take any close ups. The fulgurite found out there has glassy green fused silicates and iron minerals and is generally lumpy and ropy in appearance. minerals (2).jpg

Beach fulgurites, I've only ever found fragments, look like glass and often show dentirite like formation of how the lightning disbursed thru the sand. Fulgurite.jpg

I'm not going to say your sample is not a very worn fulgurite but it does not strike me as on in the image.
 

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P.ALLEN

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Ecuador would have a lot of volcanic and sedimentary rocks (primarily limestone). I would lean towards a "dirty" limestone or an Oolite. are the grains just really tiny round spheres? That is a sign of oolitic limestone, they are beach deposits, indicative of a modern or ancient reef.

Second thought: Might be a sandstone conglomerate as well, the grain shape and size is going to be your biggest clue. It is definitely sedimentary though.
 

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