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Strategies & Market Trends : 2026 TeoTwawKi ... 2032 Darkest Interregnum -- Ignore unavailable to you. Want to Upgrade?

To: TobagoJack who wrote (133817)	5/21/2017 4:45:04 PM
From: Elroy Jetson	Respond to of 219933

Pure 24kt gold dissolves in acids but will not tarnish, but pure gold is too soft for jewelry. Even 18kt gold jewelry tarnishes as it combines with sulfur, chlorine, phosphorous or acidic compounds. Phosphate based soaps will slowly plate 18kt gold with a dark phosphate deposit which is chemically bonded to the gold. It's tarnish, but phosphorylation rather than oxidation. Iron and steel tools are often made resistant to oxidation by prior phosphorylation to a dull black finish. Platinum is easily oxidized from exposure to sulfur or sulfides like those in smog and egg yolks and phosphates in soap becoming Pt3(PO4)4 . We use a platinum and platiunum-palladium thermocouple in our kiln but it has to be jacketed inside a porcelain tube, otherwise the sulfur gases from the kiln would quickly turn the precious metal into useless platinum sulfide and palladium sulfide which are not metals and don't conduct electricity - they'd become 100% tarnish. Placing a precious metal ring in various food dishes will at a minimum lead to a dull film of oxidized oils. A short bath in a jeweler's ultrasound polisher would make your ring shine like new again. But you will be losing ever so small amounts of precious metal in the clean.