What is Zircon? Zircon is the oldest known mineral crystal which belongs to the group of nesosilicates. They have been found in some igneous rocks which scientist believe date back 4.4 billion years ago. Its chemical name is zirconium silicate. Other interesting facts...Helium BalloonsWhat are Planets?What is a Palaeontologist?What is a Lunar Eclipse?What the difference between a Meteor and a Meteorite?