Measuring 16" in length with a 2" extension, this is a versatile necklace. The black onyx beads are approximately 5mm in size and are a "rondel" shape. The artist has placed colored spiny oyster shells, blue & green turquoise and cultured opals through out the design, giving this necklace a unique look. Onyx is a chalcedony quartz that is mined in Brazil, India, California, and Uruguay. It has a fine texture and black color; however, some onyx also displays white bands or ribbons against a black or brown background and this variety is known as sardonyx. The name comes from the Greek word onyx. Spiny Oyster Shell - also called spondylus princeps, is found in the sea off the coast of Baja California, Mexico. Spondylus is a Latin word meaning "spines on its back." Beautiful oranges, reds, white, purple. This stone of the sea carries the energies of the water, cool comfort and peace of mind from the dark depths of the sea, and a sense of understanding, patience, & knowing from the rhythm of the tides. Kingman Turquoise originates in the Mineral Park Mining District near Kingman, Arizona. One of the largest domestic turquoise mines, it is found in a large open pit copper mine in the high desert country. The Kingman Mine district was first mined by Native Americans; it was part of the most extensive prehistoric workings in Arizona.