I don't wear anything I'd class as jewellery. If I need to wear cufflinks, I chose a pair that act like tiny mirrors. There are other novelty cufflinks around, but I've seen nothing else that struck me as at all useful.

I've seen pendant whistles that would qualify. Eg Atwood's made from titanium.

I've long been interested in sun dial rings. Eg Nomos, Silver Selina Explorer, Other Shepherds Watch. There are many variations, including some that can be adjusted for latitude (which may help establish latitude if you know the time), and some which work at night (via the Pole star). I don't know how practical they are are, really, but they can be cool anyway.

Anything made of silver could have practical use against werewolves or vampires, but that'd be off-topic here.

Silver for werewolves, garlic for vampires. In most vampire mythologies, silver doesn't affect them.

But I don't know of any socially acceptable way to wear garlic.


We now return you to your original topic, sponsored by Monsterpedia: "What You Don't Know Can Kill You!"®.

In True Blood, silver affects vampires. The mythologies aren't terribly consistent.

Anyway, having been reminded by this thread, I've ordered one of the silver explorer sundial pendants for myself.

Why not reverse the concept?
Survival gear that is also jewelry? Shiny hollow military buttons (in the civil war soldiers used to keep some dollars in there for prison if they were caught). Get a small knife or tin opener decorated and use as a brooch?
And of course the chain for a necklace can be very strong wire or cord (put a weak link in so you don't hang yourself).
The Ranger Rick one has a wire saw.
There are charm bracelets that can have one charm with money in a glass fronted box. In fact money rolled up in a pen was one tip we got for escape and evasion in the army.
just use your imagination.
The Sock