April’s Mineral: Pyrite [FeS2]

Posted by : Emily | On : April 1, 2014

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In the gold rush days, pyrite was nicknamed “fools gold” due to its metallic, lustrous, dark yellow colour, and it was hastily mistaken for native gold. The name is derived from the Greek pyr, meaning fire, and alludes to its property of giving off sparks when struck on one another, or with a piece of steel. The chemical formula of Pyrite is FeS(iron disulphide) and displays striated cubes, octahedrons, or pyritohedrons when in crystal form but can also occur as aggregates or concretions. Additionally, Pyrite can chemically replace organic fossil remains in the diagenesis of sedimentary rocks resulting in spectacular pyritization of objects such as nodules, sand dollars, and ammonites.


Pyrite is associated with gold in medium- to low-temperature quartz veins, has poor to no cleavage, and can be brassy yellow. The less-foolish know that unlike gold pyrite streaks black, has a hardness of 6 to 6.5, and can show a tarnish of yellow-brown film of iron oxide. Pyrite can contain small amounts of nickel, cobalt, and even gold.

Pyrite is the most common sulphur-containing mineral and it is used in the manufacture of sulphuric acid, with iron sometimes recovered as a by-product. Metaphysically, it is said to increase vitality, enhance willpower, and aid in overcoming fear and anxiety. It is also a balancing force – so if you can’t restore your energies with an afternoon nap, you mightn’t be a fool to hold some pyrite in each hand to help you through the day!