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
Garnet rocks in which they grew. Garnet grains that lack compositional zonation commonly are interpreted as having been homogenized by diffusion, and the inferred homogenization also has implications for the temperature-time history of the host rock. Garnets are also useful in defining metamorphic facies of rocks. For instance, eclogite can be defined as a rock of basalt composition, but mainly consisting of garnet and omphacite. Pyrope-rich garnet is restricted to relatively high-pressure metamorphic rocks, such as those in the lower crust and in the Earth's mantle. Peridotite may contain plagioclase, or aluminium-rich spinel, or pyrope-rich garnet, and the presence of each