Spinel has been mistaken for ruby and sapphire in many royal jewel collections and is going up in price rapidly especially in Red, Pink and the rarest color, blue. Spinel is rarely treated or heated. There is only one known treatment for blue spinel called cobalt diffusion and we can easily detect it. Our stones have no diffusion treatments, heat or other treatments The best way to not get ripped off is to know your dealer! Most jewelers know little to nothing about blue spinel it is so rare they never encounter it. Ebay is full of fake and treated spinel so let the buyer beware.