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
Philip Stone Philip Stone Philip Stone (14 April 1924 – 15 June 2003) was an English actor, well-known for portraying film characters such as "Pa", the father of Alex DeLarge, in "A Clockwork Orange"; General Alfred Jodl in ""; Delbert Grady in "The Shining"; and Captain Philip Blumburtt in "Indiana Jones and the Temple of Doom". Stone's final film role was as the Bishop in "The Baby of Mâcon". In television, Stone is known for his roles as Brigadier Davidson in "The Rat Catchers" and Sir John Gallagher in "Justice". Philip Stone was born in Kirkstall, Leeds. Stone is the youngest of