Specimens of ruby in a matrix of feldspar and mica from Kleggåsen Ruby Quarry, Aust-Agder, Norway. Ruby is a variation of the mineral corundum, it has a red colouration and is well known as a semi-precious gemstone. Corundum is an aluminium oxide mineral and contains traces of iron, titanium and chromium which influence the crystals colour. With a hardness of 9 on the Mohs scale of hardness, corundum is used extensively in industry as an abrasive as it can scratch almost any other mineral except diamond. These samples contain small amounts of ruby within a matrix of feldspar and mica, some samples may also contain small amounts of sillimanite. The ruby may show a partial hexagonal crystal system. Specimens are supplied in a white card tray or perspex magnifier box with an information label. These are ideal samples for any mineral collector.