RCW 9.16.100

Every person who shall make, sell or offer to sell or dispose of, or have in his or her possession with intent to sell or dispose of any metal article marked, stamped or branded with the words "sterling," "sterling silver," or "solid silver," unless nine hundred twenty-five one-thousandths of the component parts of the metal of which such article and all parts thereof is manufactured is pure silver, shall be guilty of a gross misdemeanor.