Gold, Iridium, Palladium and Platinum in Reference Standard Pcc‐1 and a Komatiitic Peridotite: Implications for Selection of Igneous Rock Reference Materials for Ppb‐level Noble Metal Analysis

New analyses for AU, Ir, Pd and Pt in the USGS rock standard PCC‐1, carried out by two different radiochemical neutron activation procedures, are compared with similar analyses of a spinifex‐textured komatiitic peridotite. Better precision obtained for most of these elements on the komatiitic peridotite, in conjunction with consideration of literature values for PCC‐1, suggest that the volcanic peridotite is characterized by a more homogeneous distribution of noble metals than PCC‐1, a plutonic peridotite. These results suggest that reference materials for the analysis of sulfur‐poor mafic and ultramafie rocks with background levels of noble metals will be more satisfactory if volcanic rocks are selected.