That's what they sold as about 20-25 years ago. But now that I think about it, they're actually not very spine-y. >:^*

I googled them and that's what they're still calling them! :^)

Yes, these are the spines of a variety of slate pencil sea urchin, sample critter attached. Called slate pencil because of the resemblance of the spines to the slate pencils used by school kids with small slate tablets in the Old Days.

Thank you so much for the identification!! That's very helpful. I just did a bit of research and find that they are no close to be added to the endangered species list :-( And saw on Etsy selling from Hong Kong selling strands. So sad. I know these are vintage, so guess I can take solace that I'm not contributing to current problems.

Thank you again, learned a lot from just a small lots of bead from a necklace.

The long ones are sea urchins spicks. The small ones....I'm not sure
prob some kind of periwinkle I'm guessing on those.