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
William S. Stone Paris as air deputy to the Supreme Allied Commander Europe. Stone died while on active duty on December 2, 1968. Stone was a rated command pilot and technical observer. His decorations include the Air Force Distinguished Service Medal with oak leaf cluster, Legion of Merit with two oak leaf clusters, Bronze Star, Air Medal and the Army Commendation Ribbon William S. Stone General William Sebastian Stone (January 6, 1910 – December 2, 1968) was an American United States Air Force Major General and the third Superintendent of the United States Air Force Academy. His final assignment was as the air