Sort of depends on the effectiveness :-) But more seriously looking through my daughters old glaze catalogs there doesn't seem to be a glaze with a mix of gold and silver particulates, much less one with "exact proportions" hinted at in the article.
Given the effect of being different colors when different types of liquids were in the cup seems so novel, I found that surprising. I have no idea if I can write to the glazing company and ask them to mix me up a special glaze, but if it recreated this effect I am sure it would be popular with folks.
I think it may be because gold and silver melt too close to the temperature at which glazes are usually designed to flow. For gold the melting point is ~ 1060 deg C (Earthenware firing temperatures). I'd expect the gold might tend to coalesce rather than maintaining the sizes required to produce the effect in the OP.
Also I don't know about applying glazes to glass, only ceramics.
Given the effect of being different colors when different types of liquids were in the cup seems so novel, I found that surprising. I have no idea if I can write to the glazing company and ask them to mix me up a special glaze, but if it recreated this effect I am sure it would be popular with folks.