What do you need to know (meaning understand, not just memorize) to do spectacularly well on Quiz 6? The essential terms and concepts are listed below. Writing out answers to each of the following would be an excellent way to prepare.
Iridescence, orient, Labradoresence, adularescence, aventurescence, chatoyancy, cat'seye effect, asterism, color change, diffraction, interference, nacre, conchiolin, cleavage rainbow, opalescence, play of color, shiller, girasol effect, goldstone, cat'seye tricks: milk and honey and opening and closing, Alexandrite effect.
Defintion optical phenomena vs optical properties, define and give examples of the major optical phenomena in gemstones, structure of pearl and of its nacre, cause of iridescence, cause of orient, relationship between color and size of internal structures which cause iridescence, causes of Labradorescence, and adularescence (shiller) in moonstone, why "fire" is not a correct term for the optical phenomenon seen in precious opal, difference between common and precious opal, examples of man-made iridescence in gems, defintion and examples of girasol effect, correct spelling and pronunciation of aventuresence, chatoyance vs cat'seye effect and asterism: similarities and differences. How are cat'seyes and stars produced in cutting and viewing a gem?, how cat'seye gems are named, what causes color change phenomenon, which is the most valuable color change gem?
Labradorescence, adularescence, aventurescence, chatoyance, nacre, conchiolin, opalescence, girasol, shiller, Charoite, serefinite.