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
Emerald toucanet fruit-eater, but will also take insects, lizards,and eggs. The emerald toucanet is a popular pet toucan. It is affectionate when hand-fed and loves to play and interact with its owner. Emerald toucanets are as quick to learn tricks as cockatoos. They are active and need a large cage for their size, including perches that they can hop back and forth on. They also require a high-fruit diet, without which they are susceptible to a disease of excessive iron storage that is similar to hemochromatosis in humans. Emerald toucanet The emerald toucanet or northern emerald toucanet ("Aulacorhynchus prasinus") is a species