Coober Pedy is located where once the intertidal zone of the inland ocean reached. This is the reason why we find lots of opalised marine fossils.

Extraordinary belemnite (opalised squid) pendant. Carved crystal opal with bright green, gold, blue and a little orange. Weight 21.6carats. Width 4.5 to 10mm, length 47mm. Setting by Master Goldsmith Regine Maeckle in 18karat yellow gold. Length 63mm. Weight  9.93grams