This is Niihau shell pendant. This pendant made of blue uliuli, purple, white, yellow lenalena, brown spotted, black Momi shells with Tahitian pearl centerpiece.
Origin of shells: Niihau
Shells + pearls section measures: 2 1/2 inches (measures from end to end)
Over all necklace measures: 16 3/4 inches (Measures from end to end)
Pearl size: 8.58 mm
Findings: 14K Gold filled