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 of the three minerals defines a pressure-temperature range in which the mineral could equilibrate with olivine plus pyroxene: the three are listed in order of increasing pressure for stability of the peridotite mineral assemblage. Hence, garnet peridotite must have been formed at great depth in the earth. Xenoliths of garnet peridotite have been carried up from depths of and greater by kimberlite, and garnets from such disaggegated xenoliths are used as a kimberlite indicator minerals in diamond prospecting. At depths of about and greater, a pyroxene component is dissolved in garnet, by the substitution of (Mg,Fe) plus Si for 2Al