Volcanic & Metamorphic
Tektite
What it is
Natural glass formed not from volcanic eruptions but from meteorite impacts. When a large meteorite strikes, the heat and pressure melt terrestrial rock and blast it into the atmosphere. The molten droplets cool in flight, forming aerodynamic shapes. Moldavite, the green tektite from the Czech Republic, formed 14.7 million years ago.
How it forms
Created by asteroid impacts. The Ries crater impact in Germany 14.7 million years ago flung molten silica across what is now the Czech Republic, creating the moldavite strewn field. Supply is finite and diminishing.
Silica glass (70–80% SiO₂)
