EXPLORING THE DIFFERENCES BETWEEN COLOR-CHANGING DIAMONDS

Delving into the world of gemology there are multitudes of minerals and gemstones throughout the world. There are however a few distinct gemstones that are captivating in one unique aspect. Their ability to change color. This ability to change color is due to a variety of environmental factors. These environmental factors can be changes in lighting conditions and/or temperatures. The mechanisms behind each color change are due to atomic level changes and energy transitions. There are a specific subset of diamonds that change color due to temperature differences. These two major diamond categories that change color are chameleon diamonds and cryogenic diamonds. Their color changes are elicited by drastic changes in temperature. Chameleon diamonds exhibit a distinctive color change from grayish yellowish green to a orangy yellow when subjected to temperatures over one hundred and fifty degrees celsius. Cryogenic diamonds are the reverse, they change color from a dark grey to a light yellow color when subjected to liquid nitrogen (freezing) temperatures. Chameleon diamonds typically contain nitrogen within it’s lattice structure while cryogenic diamonds do not contain any nitrogen. The lattice defect present within cryogenic diamonds is boron. The commonality between these two diamonds is the change in the absorption of light caused by the crystal lattice within each gemstone. The change in color are caused by energy transitions within the electron band gap. The defect chemistry is unique within these gemstones, which allows these color centers to be unstable. Thus exhibiting a momentary change of color when exposed to heat or cold. Further exploration into the mechanisms of these color changes is key to understanding defect chemistry.