General name of Spondylus or commonly know as a Spiny Oyster. Found in many Oceans of the world . There are many species of Spondylus, and they vary considerably in appearance, color, size and range. They are bi-valves having two sides, hinged in the middle opening like an oyster. I collected this specimen in the mid ocean area in warm water about 10 feet. This was originally a 35 mm slide on a tripod in natural light, with a 3 second exposure. Love that color  dont you?