Moldavite is a tektite, not a mineral. A tektite forms when a meteorite strikes the earth and rocks/sediments are ejected into the atmosphere as molten rock. As that liquified material falls back to earth it instantly hardens forming a tektite aka moldavite. Because the tektite forms so quickly it lacks an atomic structure like a typical mineral resulting in an amorphous structure - no crystal formation. Tektites have been discovered across the world from different impacts, moldavite from southern Czech Republic being the most abundant.
Around 15 million years ago a meteor broke apart and impacted within modern Germany creating two craters that ejected an incredible amount of moldavite into what is now the Czech Republic. The impact of the meteorites was similar to the strength of millions of nuclear bombs being detonated simultaneously - The largest section of meteor penetrated the earth's crust and reversed the magnetic field!!! Each piece of moldavite has a unique shape and surface because of the extreme conditions it endured on its journey. The varied physical appearances such as "tear drops" versus "globs" are a result of the physics and violence each piece has endured. The dendritic patterns are a result of water erosion occurring over millions of years as the specimen laid buried. Perfect specimens (museum quality) are rare to find because surviving a fall from miles above earth and laying undisturbed for millions of years is not easy!
Centuries ago moldavite was traded and collected by ancient cultures going back to the legend of the "Holy Grail" - It has been told a green emerald from Lucifer's crown fell to Earth when he was banished from heaven and was later crafted into a cup by angels to be used at the last supper. Some years later Napoleon is said to have received the "Holy Grail" and been disappointed it resembled a piece of green glass - Just like moldavite. Examination of the mineral composition of tektites reveals they are formed from typical sedimentary rocks found on earth and not of extraterrestrial origin.
For years moldavite has been plentiful on the market but recent restrictions on mining and high demand has exhausted much of the supply of museum quality specimens. We are fortunate to have connections with dealers who have access to museum quality specimens - All of our moldavite is 100% real and each piece includes a certificate of authenticity.
Reference: Geology.com, Wikipedia and random people/stories/ideas/theories/etc