This article is a discussion of the formation of plagioclase feldspars, and explains why the occurrence of large, clean, cuttable andesine is extremely unlikely. This conclusion is supported by a nearly total lack of reports of gem andesines in the historic gemological literature.

Diffusion-treated feldspars are widely sold around the world. However, nobody has definitively proven the massive source deposits in Mongolia or Tibet, nor has the untreated material ever reached the marketplace. This article attempts to break down the current established geological thought on plagioclase feldspars;.

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The following article is an attempt to improve global recognition of feldspars - gemstones of extreme rarity which may turn out to be major players in the future of the jewelry trade.