Tiger cowrie heishi 4-5mm. Heishi literally means shells that are cut into tiny pieces drilled, strung and shaped then strung into necklaces. Cowrie shell is another sea snail smaller size but sturdy. It has a shiny with natural brown to dark speckles at the center of the dome and more solid dark coloring around the bottom of the shell. These shells are mostly used in macrame bracelets and anklets.