“Left: Subject is 27 mm across. White calcite-filled cavity from along San Francisco River Road. Right: In shortwave ultraviolet light, the calcite fluoresces light-bluish white. Strongly phosphorescent as well, the glow persists for several seconds after the UV lamp is switched off. P. Cristofono specimen and photo. Field-collected 2006. ”
Peter Cristofono - 25th February 2006