this post was submitted on 04 Feb 2025
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What is this thing?

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Let us help you identify that mysterious object you’ve found.

Currently in CHALLENGE mode: If you've got something obscure knocking about, post a picture, and let's see how we do. Please prefix such posts with "CHALLENGE:" so we know we've got a fighting chance.

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[–] klugerama 16 points 4 hours ago (2 children)

Not glass, but hardened resin. Used to track littoral currents and drift. Has metal so it can be found later with a metal detector.

[–] [email protected] 5 points 1 hour ago

A tracer pebble, interesting. But they seem to be rather made of the same pebble they are supposed to trace. https://southerncoastalgroup-scopac.org.uk/tracer-pebble-studies/

[–] Landless2029 1 points 1 minute ago

Winner. 2 hours!