Pyrrhotite is the second most common magnetic mineral in the earth’s crust.

Chemical Formula: Fe2S
Class: Ferrous Sulfides
Hardness: 3.5-4.5
Coloration: Bronze to yellow

How to identify it/Unique Characteristics or Properties:
Pyrrhotite is the second most common magnetic mineral in the earth’s crust. It is an iron sulfide with a variable amount of sulfur. That changes its’ color depending on how much sulfur it has, as well as the shape of the crystals themselves. The sample picture, above, has small yellow crystals that resemble pyrite. It can be distinguished from pyrite by being slightly more reddish and half the hardness.

Where to find it in…

The Northwest: N/A
Other: Russia, Canada, Brazil, Norway, Australia, Italy, etc
Past Uses: Pyrrhotite has been used in the past to extract the sulfur for sulfuric acid.
How it was Made: Pyrrhotite is formed when heavy minerals settle to the bottom of crystallizing magma.
Interesting Facts: It is magnetic, which sets it apart from other iron sulfides.