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 (database) was a software engineering manager from Electro Scientific Industries, and Monty Williams. Servio Logic was renamed GemStone Systems, Inc., in June 1995. The firm developed its first hardware prototype in 1982, and shipped its first software product (GemStone 1.0) in 1986. The engineering group resides in Beaverton, Oregon. Three of the original cofounding engineers, Bob Bretl, Allen Otis, and Monty Williams (now retired), have been with the firm since its start. GemStone's owners pioneered implementing distributed computing in business systems. Many information system features now associated with Java EE were implemented earlier in GemStone. GemStone and VisualWave were an early