Iron Pyrite

 

iron pyrite mineral specimen on display in a museum

 

Iron pyrite also known as pyrite or Fool's Gold is a natural mineral composed of iron and sulphur.  Although at a glance it bears a resemblance to gold, there are several characteristics which make it easy to differentiate one from the other.  The colour of iron pyrite is not as yellow as gold and pyrite is also much lighter in weight. Gold is a soft metal which grades just 2 - 2½ on Mohs scale of mineral hardness whereas iron pyrite is much harder and grades 6 to 6½. Unlike gold however iron pyrite is brittle so will shatter.  Bang a small piece of gold with a hammer and it will flatten but do the same to a piece of pyrite and it will break into hundreds of pieces.  The two minerals also have a different crystal structure and a different coloured streak, streak is a term used to describe the colour of a mineral in finely powdered form.  The streak in iron pyrite is greenish black whereas in gold it‘s yellow.

Iron pyrite is an iron sulphide which means it's a chemical compound of iron and sulphide.  It contains a high percentage of iron and is relatively common hence can be found in many environments. It comes in numerous forms and varieties and is popular with mineral collectors and for use in alternative therapies such as crystal healing.  It's common for iron pyrite to occur in cube shapes which in crystallography is known as cubic or isometric.  This is where the unit cell in a crystal system occurs as a cube and surprisingly it's one of the most common and simplest shapes found in crystals and minerals.  The face of the crystal is often but not always striated which is another feature that distinguishes it from gold.  Pyrite can also occur in massive form which literally means it occurs as a mass hence its crystal structure is not visible.

Gold and iron pyrite form under similar conditions and may also occur together in the same rocks. For that reason gold can sometimes be found as inclusions in pyrite hence it has been known to have been used as an ore of gold.

 

iron pyrite mineral specimen on display in a museum

Iron pyrite crystals from Peru.

 

The name pyrite comes from the Greek word pyr meaning fire because when struck against metal or another hard surface, it creates sparks.  This was one of the earliest methods discovered by man to create a flame.  Interestingly the wheel-lock gun developed around the year 1500 was ignited by spinning a spring-loaded steel wheel against a piece of pyrite in order to generate sparks.  The sparks subsequently ignited the gunpowder which in turn ignited the charge in the gun's barrel.

Iron pyrite which generally occurs in small quantities is a common mineral that can be found worldwide.  It would be a good source of iron were there not to be other minerals available which are better suited for this purpose.  The Rio Tinto region of Spain has vast reserves but other regions including Bolivia, Brazil, Peru, Japan, Canada and Italy to name just a few have also produced many fine specimens.  

In the world of crystal healing iron pyrite is used as an energy shield to block negative energy and prevent energy escaping from the physical body and aura.  It also strengthens confidence in masculinity and is said to be helpful for psychosomatic related issues. 

The photographs in this article were taken by Stone Mania during visits to London's Natural History museum and the Harvard Museum of Natural History, Cambridge, Massachusetts.  Our photos are copyright protected © .

 

 

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Further Reading:
More about iron pyrite on Geology.com