Fool's Gold EarthCache

As you see on a picture at the posted coordinates you will find a layer of Pyrite covered with smooth oxidized iron. It happened when lava, containing melted Iron with high consistence of sulfur have been spilled into the lake. Quickly cooling lava formed smooth surface, that cracked after long period of time.

The mineral pyrite, or iron pyrite, also known as fool's gold, is an iron sulfide with the formula FeS2. This mineral's metallic luster and pale brass-yellow hue give it a superficial resemblance to gold, hence the well-known nickname of fool's gold.

Pyrite is the most common of the sulfide minerals. The name pyrite is derived from the Greek πυρίτης (pyritēs), "of fire" or "in fire", in turn from πύρ (pyr), "fire". In ancient Roman times, this name was applied to several types of stone that would create sparks when struck against steel; Pliny the Elder described one of them as being brassy, almost certainly a reference to what we now call pyrite. By Georgius Agricola's time, the term had become a generic term for all of the sulfide minerals.

Pyrite is usually found associated with other sulfides or oxides in quartz veins, sedimentary rock, and metamorphic rock, as well as in coal beds and as a replacement mineral in fossils. Despite being nicknamed fool's gold, pyrite is sometimes found in association with small quantities of gold. Gold and arsenic occur as a coupled substitution in the pyrite structure.

Iron-pyrite FeS2 represents the prototype compound of the crystallographic pyrite structure. The structure is simple cubic and was among the first crystal structures solved by X-ray diffraction.

Chemical weathering transforms the crystals of pyrite into limonite by hydrating the molecules, but the external shape of the pyrite crystal remains. Because of its amorphous nature, and occurrence in hydrated areas limonite often presents as a clay or mudstone.