Abstract: A holder for supporting an elongated tool in an upright position on a planar surface. The holder comprises a body defined by a semicircular or semielliptical section of a longitudinal section of a hollow cylinder, the body having a thickness from an interior wall to an exterior wall, the holder configured to stand with the radius of the semicircular or semielliptical section perpendicular to the planar surface. A through-hole in the body is sized to accommodate a periphery of the tool. A tool and holder system may include the holder and an elongated tool having a generally cylindrical geometry, such as a curing tool configured to emit radiation having a predetermined wavelength for curing a dental resin.