Any activity that has, or is about to celebrate, its diamond anniversary has been going on for a long time. The silver and gold anniversaries are long since past. One has to wonder why platinum is not the next milestone. It is rarer than gold, often more expensive, and to some just as beautiful. The leap from fifty years to sixty years deserves more than just another rare metal, however. It is traditionally celebrated by a far more unusual mineral: diamond. Why more unusual? Most are atrociously old, more than 1 billion years and some even 3 billion years. They have originated at great depth, many tens of kilometers at or near the crust-mantle boundary. Their conditions of formation are so extreme that they can hardly be duplicated in the laboratory. Their cost when in gem varieties can be measured in thousands of dollars per gram as compared to gold or platinum's paltry $50 per gram. Diamond's optical and physical properties are unusual, resulting in both beauty of finished product and durability such that as a detrital grain it can travel many hundreds of miles under alluvial conditions with nary a scratch. It is the object of one of the most continuous advertising campaigns, one that has resulted in its being a girl's best friend, a must-have for any serious engagement.
Dr. Robert B. Cook, an executive editor of Rocks & Minerals, is a professor emeritus in the Department of Geology and Geography at Auburn University.