That would be a broken Lantern Moon rosewood needle, US 6/4 mm. A tragedy. Those were my favorites.
I'm not even sure exactly what happened. I feel pretty confident, though, placing blame on my knitting storage situation, which looks like this:
One Rubbermaid tub, jammed full of everything: yarn, needles, tools, books, project bags, etc, etc. I've probably mentioned that most of our stuff is in storage in Florida; what we have in Rhode Island is pretty much confined to tubs like these. So when digging through there to find a specific yarn or stitch marker or whatever, well, you can imagine what might happen if a delicate wooden needle got loose amongst the mess, got one end jammed securely in a corner behind a book, got the other end through a loop of yarn, and was pulled or pushed too hard... Or maybe you don't have to imagine - just refer to the first picture.
When I get to Jacksonville, I will be organized, and things like this should not happen anymore. Then again, I am a gigantic klutz, so in reality these little accidental tragedies will probably continue the rest of my life. Sigh.