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
Prehistoric beads in the Philippines of the shell beads found in sites were actually cut beads. This shows that there was a significant development of technique and method to be able to design these shell beads, as modification after the cutting process would have been substantially difficult. Francis discussed in his study of the Philippine shell bead collection, that the beads may have been around since the Late Neolithic period and were later replaced by glass and other inorganic beads from about 200 BCE – 1200 CE. Glover and Henderson place the date of glass bead trade in Southeast Asia at no later than 400