A family of reflectin proteins is identified herein that is deposited in flat, structural platelets in reflective tissues of the squid Euprymna scolopes. These proteins are encoded by at least six genes in three subfamilies and have no reported homologues outside of squids. Reflectins possess 5 repeating domains, that are remarkably conserved among members of the family. The proteins have a highly unusual composition with four relatively rare residues (tyrosine, methionine, arginine, and tryptophan) comprising .about.57% of a reflectin, and several common residues (alanine, isoleucine, leucine, and lysine) occurring in none of the family members. These protein-based reflectors in squids provide a striking example of nanofabrication in animal systems.