title: Pholidostrophiid brachiopods: origin of the nacreous luster.
abstract: The "nacreous" luster characteristic of the pholidostrophiid group of fossil brachiopods results from a shell structure that produces superimposed sets of natural optical-diffraction gratings made of calcite. The wall structure is crossed lamellar, parallel to the shell surfdce; thus flakiness and development of reflecting surfaces are facilitated.
authors.forename: K M
authors.initials: KM
authors.lastname: Towe
authors.forename: C W
authors.initials: CW
authors.lastname: Harper