Microscopic filaments of metal such as zinc and tin that "grow" out of coated metal surfaces. In particular, zinc whiskers can be dislodged from the metal tracks of raised flooring, migrate via heating and air conditioning ducts into electronic equipment and cause short circuits if they settle onto circuit board surfaces. For more information on metal whiskers, visit http://nepp.nasa.gov/whisker.
The bright filaments are zinc whiskers emerging out of a scratch in the zinc plating on the underside of a 10 year-old raised floor tile from a computer room. According to Peter Bush, consultant to the International Electronics Manufacturing Initiative (www.inemi.org), there were some two million whiskers on this tile. (Image courtesy of Peter Bush, State University of New York at Buffalo.)