Quartz is one of the most common minerals on our planet. In natural light, it varies from completely colourless to a wide range of hues (purple, yellow, orange, black), making it particularly popular with collectors. The specimen on display is from the Besalampy district of Madagascar. It is a perfect crystal with a vitreous shine and a particular “spotted” fluorescence when lit up with ultraviolet light. The fluorescence of minerals is due to the movement of electrons induced by the presence of impurities within. Indeed, in pure crystals this phenomenon is generally non-existent. In this quartz crystal, small fluid inclusions of hydrocarbons trapped during its growth generate a typical light blue fluorescence.
