Gem-quality pink fluorite from Planggenstock, Switzerland: chemical and physical properties and a comparison with pink fluorites from other localities

Noble gases —elements of the last column of the periodic table—are chemically defined by their f

Gem-quality sapphires containing ‘exotic’ elements such as Sn, Nb, Zr, Ta, W, are of special int

Corundum, encompassing the highly prized ruby and sapphire varieties, stands as a cornerstone of the