British Tourmaline within a Granite Matrix, found in the China Clay pits of Cornwall. Tourmaline is crystalline mineral which is also classified as a semi precious stone due to the various colours it can be found in and the often high quality of their crystals. It is a boron silicate compound which usually appears jet black in colour and is known to exhibit pyro-electric properties because it was found to attract hot ashes. The jet black and dull Tourmaline is juxtaposed with the lighter granite, and while the felsic granite provides the majority matrix. overall,the sample measures 80 x 80 mm in size with some tourmaline crystals measuring 20 mm in length. This display piece is ideal for a serious collector, particularly those with an interest in minerals from the UK; it comes supplied with a white card tray and accompanying information label.