Well, not a lot to say. I'd never seen anything like it ... and so here it is:
That is my hand in the picture ... and the ring is a true 9. Whomever carved it ... and the carving is beautifully detailed ... must have been ashamed to or afraid to sign the piece. It is sterling and it is turquoise ... and the carving is bone. Very well made; my silversmith bud Ronson Page says re-sizing .. or changing band size is not a big deal.
Stamped STERLING: Stones are beautiful; might be Cerillos ... but will get a solid opinion shortly. Deep Deep blue with a bit of green and not too much matrix. Well done piece and it is vintage vintage ... back at a time when Horned Toads were as common as Jack Rabbits.