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 2015. "GemStone IV" is a text-based game built on Simutronics' proprietary engine, the IFE (Interactive Fiction Engine). This engine is capable of changing nearly any aspect of the game on the fly which allows updates without the necessity for downtime. Due to the use of the IFE, "GemStone" is rarely taken offline, giving a 24-hour uptime cycle aside from the occasional game crash. The "GemStone" interface is simply a text stream, and the game can be played with a Telnet interface after authentication. There are several official interfaces to the game, as well as several unofficial ones. The oldest interface