OREAS 265

OREAS 265 is a low-grade gold certified reference material produced from a blend of oxide gold ore and a suite of barren volcanic and sedimentary host rocks sourced from multiple Australian geological terranes.

The blend incorporates oxide gold ore from the Agate Creek district, combined with barren lithologies including Tuscan Rock, Ettamogah quartz-rich units, and basaltic scoria. The mineralogical character of the blend reflects weathered felsic to intermediate volcanics containing dispersed gold ± accessory sulphides, typical of low-grade oxide gold deposits subjected to lateritic and supergene processes.

OREAS 265 has been characterized using the following methods:

• Gold by Pb collection fire assay (25-50g charge weight) with AAS and ICP-OES finish
• Gold by Bi collection fire assay (30 g charge weight) with AAS finish
• Gold by PhotonAssay™
• Gold by 15-50g aqua regia digestion with ICP-MS and AAS finish
• Gold by cyanide leach (20-200g) with AAS or ICP-MS finish
• Full ICP-OES and ICP-MS elemental suites by 4-acid (HNO3-HF-HClO4-HCl) digestion
• Full ICP-OES and ICP-MS elemental suites by aqua regia digestion

Certified values for applicable analytes are operationally defined for each method, with results under OREAS ISO 17034 scope of accreditation.