This term is supposed to mean a gold powder so fine that it consists of single atoms not joined by metal bonds to neighboring gold atoms. Ingesting such a substance is claimed to bring about 'all kinds of spiritual benefits. The theme was launched by David Hudson in the 1980's in the US. David Hudson has now long been out of business but the idea lives on and other manufacturers market products called monoatomic gold, white powder of gold and other various names.
The Cassiopaea material describes use of this as the ultimate spiritual entrapment, akin to selling one's soul.
Papers in the field of molecular biology and genetics have been made about the possibility of bonding single atoms of gold with the DNA helix. Radio frequency EM fields can then cause these gold particles to vibrate, thus heating the DNA and influencing its chemistry. The gold particles offer a handle on the DNA molecule, as it were. This would lend some credence to the claims that monoatomic gold may indeed have some effect on DNA, at least in terms of making this increasingly sensitive to remote influences.
Claims from the promoters of monoatomic gold as a 'technology of ascension' include all manner of strange psychic occurrences, including a person who started experiencing increasingly frequent, involuntary 'spiritual orgasms.' This may not be literally false but should give rise to some questions.
We may infer with some probability that monoatomic gold indeed can deliver one even further in the hands of outside forces not of one's choosing. We may also put this together with the Cassiopaea channeled information stating that 'light waves were used to cancel the 10 first factors of DNA' in the context of the mythical Fall. Monoatomic gold may be a device to a similar effect.