Concretions are found in sedimentary rock or soil, often ovid or spherical in shape. They generally form around some type of nucleus, usually early on in the burial history of the sediment. This makes them harder than the surrounding host sediment. Record of these geological curiosities dates back to the 18th century. They were often confused with fossils of dinosaurs, plants, humans and extraterrestrials. The name concretion is derived from Latin; con (together), crescere (grow).
Pyrite, which is iron sulfide, has been easily confused with gold. Hence, the nickname, Fool's Gold. It gets its name from the Greek pyr meaning fire because it gives off sparks when hit with a metal.
It is believed that possession of pyrite attracts money. Some use Pyrite to stimulate the intellect and enhance recall of information. Good for those of us who can be forgetful.
No two pieces are alike. Each one will slightly vary in size, shape and colour.