Olivine is Peridot in its basic form and an abundant mineral. It is not formed in the Earth’s crust, but deeper, in the molten rock of the upper mantle, and brought to the surface by earthquakes and volcanoes. Some Olivine is not from Earth, found in meteorites formed 4.5 billion years ago. It was also found in the comet dust on the Stardust space probe on its return to Earth in 2006. It occurs in shades of light olive to brownish olive with occasional dark inclusions.