DNA security beads. Coloured scanning electron micrograph (SEM) of CypherMark DNA (deoxyribonucleic eic acid) security beads in the crevice of a diamond. The microscopic beads are used to uncounterfeitably mark both liquids and solid surfaces as they have a unique DNA sequence attached to them. Here, some beads have lodged in a surface cavity of the diamond. Analysis of the DNA code allows the diamond to be identified, protecting against theft. CypherMark beads can also be used in sprays to mark criminals and in the identification of the source of oil spills. Photographed at Cypher Science Ltd. in Cardiff, Wales. Magnification: x1240 at 6x7cm size.