Yea, I'm no expert but it doesn't resemble a glass bottle, and on the other hand emeralds shouldn't be found on the beach in Ca. I've never heard of that before.
Central California is known to have quite a bit of jade in some places. Maybe some drifted down. If it isn't just melted glass, I would lean strongly toward it being jade rather than emerald. Emerald would be cool though.
Clean it up and let it sit at room temperature for awhile. Touch it and if it still feels somewhat cool, it could be jade.