A moldavite is a natural olive-green tektite glass which formed about 14.7 million years ago when a meteorite impact occurred in Southern Germany. This meteorite impact formed the Nördlinger Ries crater and caused the formation of the moldavite glass. Moldavite tektites are chemically made up mainly of silicon dioxide and aluminum oxide.

Moldavites contain more silica than any other type of tektite which produces their green color. Bohemian moldavite types have a greater SiO2 content than the Moravian moldavite types. Bohemian moldavites are mostly variations of green from pale to a rich bottle green color.