By Gary Roskin, G.G., FGA

The recent saga of the gemstone andesine illustrates the complexities of gemstone enhancement and disclosure.

Andesine is a reddish-orange feldspar that's been in the market five years. It's sometimes called sunstone because its chemical composition is similar to that gemstone's. Stuart Robertson, research director for Gemworld International, Glenview, Ill., says it was first seen at the gem shows in Tucson, Ariz., in 2003, but didn't draw attention until 2005, when quantities started to increase. Color and clarity were remarkably consistent, raising questions about origin and enhancement. Some have answers to those questions. Some of the ...