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 industry in Greenland gemstone ruby. The native inhabitants continued to assist the European explorers with their ruby exploration, leading them to some half dozen locations, spread out for over a hundred miles along the southwest shores of Greenland, known as the Kitaa Coast. Ruby and pink sapphire are the red and pink varieties of the mineral corundum, an aluminum-oxide mineral Al2O3. The pink/red colour is formed in corundum by adding the element chromium to its crystal structure. Spectroscopy of rubies from the Aappaluttoq occurrence in Greenland confirm the presence of chromium as well as showing absorption in the UV region indicating high Fe