Gold parting in 1860's Australia. It is able to refine gold up to 99.5% purity. The process involves blowing a stream of chlorine gas over and through a crucible filled with molten impure gold. Impurities in the gold form chlorides before the gold does and these insoluble salts are removed from the melt by skimming the surface. Invented by Emil Wohlwill in 1874, this produces the highest purity gold (99.999%). It is an electrolytic process using pure gold for the cathode (or titanium as a starter cathode) and chloroauric acid (gold chloride-hydrochloric acid) as the electrolyte; this is made by dissolving gold
Commodity (Marxism) of value, product-values in an open market are regulated by the average socially necessary labour time required to produce them, and price relativities of products are ultimately governed by the law of value. Commodity-trade, Marx argues, historically begins at the boundaries of separate economic communities based otherwise on a "non-commercial" form of production. Thus, producers trade in those goods of which those producers, have episodic or permanent surpluses to their own requirements, and they aim to obtain different goods with an equal value in return. Marx refers to this as "simple exchange" which implies what Frederick Engels calls "simple commodity