Most fossils are created when the biological material of a plant, insect or animal is replace by opal, chalcedony or other minerals over millennia. The mineral takes on the form of the biological matter within the surrounding rock formations or within sedimentary layers.
Amber, Jet, Petrified Wood, Sand dollars, and Ammonites are some examples of fossils.
Revered by many cultures for centuries, fossils, because of their age, are often used as talismans for protection and long life. They are links to the past and, as such, can be helpful for past-life visualisation, astral travel and increased knowledge of ancient ways. Fossils are associated with the earth element, which can heighten your intuition, especially when learning about crystals.