Mineral site, and from there further subdivided by the chemistry of the W site. The Y and Z sites can accommodate a variety of cations, especially various transition metals; this variability in structural transition metal content gives the tourmaline group greater variability in colour. Other cyclosilicates include beryl, AlBeSiO, whose varieties include the gemstones emerald (green) and aquamarine (bluish). Cordierite is structurally similar to beryl, and is a common metamorphic mineral. Sorosilicates, also termed disilicates, have tetrahedron-tetrahedron bonding at one oxygen, which results in a 2:7 ratio of silicon to oxygen. The resultant common structural element is the [SiO] group. The
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