1) Crystal 2) Natural glass 3) Quartz 4) Quartz glass 5) Vitreous silica 1) Quartz 2) Quartz glass 
Lechatelierite is silica glass, amorphous SiO2. One common way in which lechatelierite forms naturally is by very high temperature melting of quartz sand during a lightning strike. The result is an irregular, branching, often foamy hollow tube of silica glass called a fulgurite. Lechatelierite also forms as the result of high pressure shock metamo...
a natural silica glass (silicon dioxide, SiO2) that has the same chemical composition as coesite, cristobalite, stishovite, quartz, and tridymite but ... [2 related articles]
Silicon oxide, di-