Optical effects produced in gemstones from the feldspar group

Abstract

This article reviews the optical effects of feldspars, a group of minerals with various applications, including jewelry. Feldspars are divided into alkali and plagioclase, and exhibit effects such as adularescence, labradorescence and aventurescence, depending on the mineral intergrowth. The article discusses the gem varieties of feldspar, such as moonstone, labradorite and sunstone, and highlights the importance of crystal orientation in cutting to maximize the optical effects. The article concludes that more research on the optical properties of feldspar can improve gem processing techniques and mineralogical knowledge.