Conventional wisdom is that gold not assayable is not recoverable or does not exist. There has been no formal study on the possibility that gold assays using advanced spectroscopy such as mass spectrometry and neutron activation could grossly underestimate the gold recoverable by proprietary extraction techniques._x000D_
Such gold is not considered here to be invisible' to detection but rather abnormal' or distorted' at atomic level. Large-scale extraction of gold from abnormal' ores has not been demonstrated, hence this emerging field still lacks credibility and acceptance. For fear of harming their reputation, few academic researchers or companies are expected to venture into this field until it is well proven. This paper aims to create awareness amongst metallurgists of the potential of abnormal' gold ores by reviewing unconventional observations, the pseudoscience mainly available in non-peer reviewed web sites, and hypotheses for the recovery of non-assayable' gold, including: the occurrence of high levels of nano-sized gold in clays detectable by high-precision analytical instruments, which represents invisible' gold accounts of ambient transmutation of elements, mainly using thermal methods orbitally rearranged monoatomic elements (ORMEs), which are virtually undetectable by conventional means, and their conversion to normal metals the possibility of a high spin' state of transition metals the formation of microclusters altering the chemical behaviour of gold and the possibility of clustering with other elements._x000D_
It is suggested here that gold in ores displays a range of clustering, from normal' gold amenable to conventional extraction to the ORME state. The concepts of intermolecular water' in forming complex salts locking up precious metals, electro-dissolution in strong acids, and electrowinning at both the anode and cathode are discussed as a means of treating abnormal' gold ores. It is also possible that the gas phase extraction of gold chlorides under controlled temperature and pressure conditions, as well as transferred-arc plasma fuming of gold through carbothermic reduction of sulfides, could be used as a basis for extraction of gold from abnormal' ores.CITATION:van Deventer, J S J, 2013. Is there gold that we do not recognise?, in Proceedings World Gold 2013, pp 27-34 (The Australasian Institute of Mining and Metallurgy: Melbourne).