Lechatelierite belongs to inhomogeneities in moldavites. It is a particle of pure quartz glass (lechatelierite contains 99% of SiO2.) made by melting quartz mineral grains.
Its grains are usually elongated and often twisted. Lechatelierite is more resistent to etching than surrounding glass (about 120 times higher resistance). It sometimes forms points coming out of the moldavite. They can be up to several milimeters long (supposedly even 1cm). Lechatelierite is more frequent in moldavites from the region of Ceske Budejovice and Trebon.