Shell money most valued by the Native American tribes of the Pacific Coast from Alaska to northwest California was "Dentalium shell", a species of long narrow marine shelled mollusk, a tusk shell or scaphopod. The tusk shell is naturally open at both ends, and can easily be strung on a thread. This shell money was valued by its length rather than the exact number of shells; the "ligua", the highest denomination in their currency, was a length of about 6 inches. Farther south, in central California and southern California, the shell of the olive snail "Olivella biplicata" was used to make beads
Puka shell because they were naturally pierced, which enabled them to be strung like beads. Puka shell jewellery first became a popular item in Hawaii during the 1960s, as an attractive and inexpensive lei which could be made and sold on the beach where it was made. In the 1970s, this type of shell jewelry became highly sought after, and prices skyrocketed. The craftsmanship also became more refined and the "lei pūpū puka", puka shell leis were strung in graduated or matching styles, rather than the original random patterns. Many "legends" about the puka shell were created during this time, and these