Blue sapphire of gem quality was recently discovered in spinel–chlorite–muscovite rock
within meta-ultramafites near the Ilmenogorsky alkaline complex in the Ilmen Mountains of …

In the Hellenides Orogen, minerals of various gem quality occur in various rock types from
mainly four tectono-metamorphic units, the Rhodope, Pelagonian, and the Attico-Cycladic …

Abstract The Papôa Volcanic Breccia (Peniche, West Portugal) is a Mesozoic pyroclastic
deposit that includes numerous igneous and metamorphic xenoliths belonging to the …

Greece contains several gem corundum deposits set within diverse geological settings,
mostly within the Rhodope (Xanthi and Drama areas) and Attico-Cycladic (Naxos and Ikaria …

Primary rubies in the Ailao Shan of Yunnan Province, China, are found in three layers of
marble. However, the origin and source rocks of placer rubies in the Yuanjiang area remains …

In this study, the oxygen isotope (δ18O) composition of pink to red gem-quality rubies from
Paranesti, Greece was investigated using in-situ secondary ionization mass spectrometry …

Corundum primary deposits in Greece occur in four locations: Paranesti in Drama and
Gorgona in Xanthi, both belonging to the wider Rhodope Massif, as well as, Ikaria island …

Abstract Baffin Island's Lake Harbour Group (LHG), a Paleoproterozoic granulite facies
metasedimentary sequence rich in carbonates, contains occurrences of the gemstones …

Microscopic, non-gem quality, grains of blue sapphire (corundum) have been identified in a
small (1–2 cm wide), discontinuous, dike of nelsonite hosted by aluminous feldspathic …

Corundum is formed in a variety of geological settings, but it is quite rare, because it requires
a silica-depleted (otherwise, aluminum is included in aluminosilicates-feldspars, micas) and …