Each display features a gem in its three stages of transformation: raw crystal, cut and polished stone, and mounted jewel in a finished ring, brooch, or necklace. Experts judge gems according to ...
Raw moldavite has a rippled, flattened shape ... The most valuable stones are usually smaller in size and under one carat, as larger stones are too dark and look almost black. Gem silica is a rare ...
In describing colored gemstones, the major factors influencing color are hue (position of a color ... For more on the behavior of light entering a crystal, see box A. Visible light is one form of ...
Le Thi-Thu Huong, Tobias Häger, Wolfgang Hofmeister, Christoph Hauzenberger, Dietmar Schwarz, Pham Van Long, Ursula Wehmeister, Nguyen Ngoc Khoi, and Nguy Tuyet Nhung ...