Fulgurite (from the Latin ¨fulgur¨, 'lightning') is a tube shaped metamorphic rock, composed of lechatelierite (glass silica) that can be found in sands or sandstones. Its formation is due to the strike of an atmospheric lightning. The lightning strike on a sandy land causes the fusion of silica beads, since the temperature can reach 4000 degrees Celsius and up to a depth of more than one metre, but in a very narrow area. This way the silica is glazed in the shape of tubes of beam, from 2 to 50 mm in diameter, sometimes twisted or branched. These fulgurites can be found in the deserts of sand and coastal dunes. The formation of fulgurites is a rare phenomenon, and extracting a whole one is complicated because of the fragility of the mineral, which is easily breakable. The fulgurite of this lot has an amazing size, very large and rare in this type of formations, being one of the largest that can be found. An authentic specimen worthy of a great collection. Best regards. Adrian Contreras. IMCA #7412.