Gemstone usually found in. For example, diamonds, which have a cubic crystal system, are often found as octahedrons. Gemstones are classified into different "groups", "species", and "varieties". For example, ruby is the red variety of the species corundum, while any other color of corundum is considered sapphire. Other examples are the emerald (green), aquamarine (blue), red beryl (red), goshenite (colorless), heliodor (yellow) and morganite (pink), which are all varieties of the mineral species beryl. Gems are characterized in terms of refractive index, dispersion, specific gravity, hardness, cleavage, fracture and luster. They may exhibit pleochroism or double refraction. They may have luminescence
GemStone IV all players to begin anew. "GemStone III" evolved into "GemStone IV" in November 2003, but the game world and character records were maintained over the transition. "GemStone III" was promoted on GEnie by promising players the opportunity to receive real-life versions of gems found in-game, something that persisted for many years. "GemStone" originally operated with a license to use the Rolemaster game mechanics and Shadow World environment from Iron Crown Enterprises (ICE). In 1995, Simutronics and ICE agreed to let the business relationship expire, necessitating the removal of all ICE intellectual property from "GemStone". Many of the game changes were