| My guess also leans towards Abalone: Haliotis rufescens.
Another possibility would be Tahitian Blister...most of the ones I've seen have a flat dome, like the one in the center of the photo (left to right: Pteria penguin, Pinctada margaritifera, P. maxima).
Your photo needs a close-up in order to catch more of the surface and the colors present.
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Douglas McLaurin, M.Sc. Aquaculture
Perlas del Mar de Cortez
Guaymas, Sonora, Mexico
perlas.com.mx
The Pearl is a Harsh Mistress...and I am its Humble Servant |