Giant clams, known in Chamorro as "hima", were significant to the ancient Chamoru people in many ways and today are still considered a prized food delicacy, in addition to the large shell of the giant clam which is used for making authentic Chamorro jewelry on the island of Guam.  Today many Chamorros and Guamanians (people from Guam who are not native Chamorros) proudly wear necklaces, pendants and other jewelry made out of the hima's shell.

     Four different species of hima are known to live in the waters around the island of Guam.  These species include the Tridacna maxima, Tridacna squamosa, Tridacna gigas, and Hippopus hippopus. Most likely due to overharvesting, the latter two species of hima mentioned above are believed to be extinct on Guam while the remaining two hima species are still found in the waters around Guam.

     The larger of the two, T. squamosa is rare, and the smaller one, T. maxima, lives tightly attached to rocks and coral on the ocean floor around Guam. They are most common in areas with strong currents or in shallow waters beyond the protective reef which surrounds most of Guam.

     Tridacna derasa, the lagoon giant clam which is plentiful in Palau and which was intentionally introduced to Guam to help establish the giant clams on the reefs around the island have been successfully raised in Palau and sold to Guam and other Pacific Islands.

     The shell of the hima have thick hard hinges on both halves of the shell which Chamorro's traditionally ground down to make tools like fishing hooks.  Even under the best conditions, it takes many years for hima to reach a large enough size for the shell to be used for making jewelry.

     Because hima are on the borderline of being an endangered species in many areas where they are found and are practically extinct in some areas where they use to live around the Pacific, hima can only be taken for home consumption four months out of the year on the island of Guam in order to conserve the species and ensure they don't become extinct. There are many rules and restrictions to harvesting hima on Guam and in other areas around the world where hima can be found, making it even more desirable and sought after as a food delicacy and for making jewelry.