The Science of Gemstones

Catalog description

From Biblical times to the present, gems and precious metals have served as the standard by which empires have measured their worth. Through the ingenious marketing of an international cartel, diamonds have become identified with the oldest and most sacred of human contracts. To what can we attribute the unique allure of beautiful minerals? In this course, students will learn the underlying science of what distinguishes a gemstone from dross. A broad historical introduction will trace the social role that gemstones have played in human history over tens of thousands of years. After a review of the properties of atoms, they will learn the connections between atomic bonds and the physical hardness that has preserved diamonds and other gems against billions of years of abrasive forces. Students also will engage in directed discussions of ethical issues raised by gem materials: Why are gems so costly? Is it moral to purchase an expensive gemstone? What ethical hazards do synthetic gems pose? In addition, the course will explain the surprisingly simple physical processes that account for the magnificent optical properties of gemstones. Students will understand in a quantitative way how the bending of light (refraction) within a gem produces its sparkle: how variation in refraction generates fire (dispersion); how the interference of light rays from periodic structures in some rare gems like opal can yield colors that change with viewing angle (diffraction); and how vanishingly small traces of impurity atoms can generate the deep coloration of rubies, sapphires, and emeralds. In addition, students will learn about the atomic symmetries that govern the physical character of gemstones and allow modern mineralogists to distinguish imposters from real gems.