You will find purists who turn up their noses as jewelry made from treated turquoise. Natural turquoise is preferred by all, but its availability is limited nowadays. As a collector, I have discovered that my Southwestern souvenirs, rare or not, often fare poorly in East Coast pollution. Over the years, cracks and chips develop even in the best stones. Some of the techniques used on treated turquoise give contemporary stones a fighting chance against air-borne contamination. Learning the definitions for stabilized, enhanced, oiled or waxed, fracture sealed, reconstituted, and dyed turquoise makes the collector a better consumer. Buy from a vendor or seller who is ready to disclose what kind of turquoise is in their product.