Gemstone value of the stone. Some treatments are used widely because the resulting gem is stable, while others are not accepted most commonly because the gem color is unstable and may revert to the original tone. Heat can improve gemstone color or clarity. The heating process has been well known to gem miners and cutters for centuries, and in many stone types heating is a common practice. Most citrine is made by heating amethyst, and partial heating with a strong gradient results in “ametrine” – a stone partly amethyst and partly citrine. Aquamarine is often heated to remove yellow tones, or
Gemstone Publishing then to Gemstone, which has been the home of Cochran's EC reprints for over 15 years. Reprinting the Cochran/Gladstone-reprints of "The Haunt of Fear", "The Vault of Horror" and "Weird Science" (all 1992), Gemstone also republished (in single issue and 'annual' - four issues per 'annual' - format): Oversize, hardback, slip-cased collections of these comics had been previously published in black & white by Cochran during the 1980s as "The Complete EC Library". This Library was then added to by Cochran/Gemstone with 2005's "Picto-Fiction" collection, comprising the EC comics: "Confessions Illustrated", "Crime Illustrated", "Shock Illustrated" and "Terror Illustrated", along with