Spiny Oyster Turquoise Sterling Silver PendantTwo materials that built the visual language of Southwest jewelryone from deep in the earth, one from the ocean floor. Turquoise is a copper aluminum phosphate (CuAl(PO)(OH)4HO), its blue green color a direct expression of copper content; it forms in arid, copper rich ground where percolating groundwater carries copper ions into fractured host rock. The spiny oyster shell is organicharvested from Spondylus species, bivalve mollusks related to scallops