Marcasite - Mineral Properties
Will the Real Marcasite Please Stand Up?
The world of gemstones and minerals is full of confusing common names and outright misnomers. The gemstone called Marcasite is no exception..
All of the so-called marcasite used in jewelry is actually a mineral called Pyrite. There IS a mineral named marcasite which is similar in appearance, but the "real" marcasite is far too brittle and too unstable to be put to any practical use (though an attractive speciman, like the one on the left, might look nice in a display case or bookshelf.)
Composition and Mineral Properties
Pyrite - Chemical Composition: FeS2
Specific Gravity: 5.0
Hardness: 6 - 6.5
Luster: Metallic
Transparency: Opaque
Crystals: Cubic
Where Found: Worldwide, but mined primarily in the United States, Brazil and Peru.
That said, let's take a look at Pyrite - the stone we've come to know and love by its popular nickname, marcasite.
Pyrite (or chemically speaking, Iron Sulfite) gets its name from the Greek word "pyr" or "fire" because it makes a spark when struck with metal - a property which also makes it a notorious cause of mining fires. It is a common mineral, found throughout the world, typically as deposits of small cubic crystals just a few millimeters in size, though larger crystals are not uncommon.. It is frequently found near veins of quartz or coal.
Pyrite can be recognized by its gleaming, brass-like surface. At first glance, pyrite sparkles like flecks of gold, hence yet another nickname: Fool's Gold. It has tricked many an unsuspecting gold prospector into thinking they've found the real thing!
Pyrite is a moderately hard and durable stone - about as hard as a garnet. With a specific gravity of 5.0, it is quite heavy relative to its size. Unlike hematite, another dark stone with a metallic appearance, pyrite is never magnetic.
CC attribution for mineral photos this page: Rob Lavinsky, iRocks.com – CC-BY-SA-3.0.