A composition comprising an organic crystal having a minor axis length of from 3 to 100 nm and a major axis length of from 10 to 2,000 nm and a matrix material, wherein the organic crystal satisfies that (1) a surfactant is adsorbed on the organic crystal, (2) an inorganic ion is adsorbed on the organic crystal, (3) silicon oxide, titanium oxide, aluminum oxide, zirconium oxide, barium oxide or hydroxyapatite is bonded with the organic crystal, or (4) the organic crystal is modified with a group represented by the following formula (1): wherein L1 represents —O—, —S—, —CO— or others, n is 0 to 4, and R1 represents an organic group.