, Volume 18, Issue 3, pp 86-91,
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Colloidal gold. Part I


Colloidal gold has a long history (1). Gold’s lustre, chemical stability and high price fascinated many ancients. Its preparation to give beautiful ruby red ‘solution’ intrigued the alchemists. Unusual medical properties were ascribed to this ‘potable gold’ and hope was expressed that this may be the ‘elixir of life’. This hope found a modest realization in the ‘Danziger Gold’, an alcoholic concoction containing finely-divided gold. Still available, its exhilarating effects are due not to the gold but to its alcoholic content. Gold ruby glass was manufactured at the end of the 16th century and the ‘Purple of Cassius’, prepared by the reduction of soluble gold salts by tin chloride, has been known since the 17th century.