JCK preps you on gem prices (high), trends (have we mentioned blue?), and best buys ­(small stones) so you can shop the ­Tucson shows like a rock starIt’s February: Let the Tucson gem shows begin! The annual Arizona gathering of the world’s gem dealers, rock hounds, crystal sages, and purveyors of gem and mineral bric-a-brac kicks off at the beginning of the month, meaning it’s time to dust off your cowboy boots, put your diet on hold (the local Mexican cuisine is a must), and prepare your open-to-buy.Besides the big story on ever-increasing gem prices, expect to encounter the same gemstone treatments that have been percolating for years—lead- and silica-glass–filled rubies, beryllium-diffused stones, titanium-­diffused synthetic sapphires (sold as natural stones), and cobalt-coated tanzanite (to enhance color). Not everything, however, is same same. Below we bring you five