It consists of a few ultramafic lamprophyre dikes hosted by limestone, in which are scattered sapphire crystals, typically a saturated blue, with a small number of violet-colored stones. The nuance of blue is typical of sapphires with low iron, and the violet color indicates the presence of minor Cr. Habit is typically rhombohedral and flat. The origin of these sapphires is suspected to be metamorphic xenocrysts