OREAS 257

Certified Reference Material (CRM) OREAS 257 was prepared from gold-bearing Wilber Lode oxide ore from the Andy Well Gold Project. The Wilber Lode is a shear- hosted, narrow vein, quartz lode-style gold deposit situated within the Meekatharra-Wydgee greenstone belt in the Archaean Yilgarn Craton of Western Australia. The common primary mineral assemblage as stated by Mason and Harris (2011, 2012, cited in Hingston et al, 2014) is quartz, calcite, chlorite, fuchsite, pyrite, galena, sphalerite, chalcopyrite and gold. The host rock consists of a complex sequence of weathered Archaean meta-basalt and meta-porphyritic rocks derived from a primary mineralogy of albite, actinolite, chlorite, sericite, biotite, calcite, zoisite, muscovite, quartz and titanate. The Andy Well deposit is located approximately 45km north of Meekatharra in the Murchison region of Western Australia. OREAS 254 is one of a suite of five oxide gold CRMs ranging in gold content from 1.2 to 14ppm.