Pyrite (Iron Pyrite) "Fools Gold"

Pyrite

PyritePyrite is the classic "Fool's Gold". There are other shiny brassy yellow minerals, but pyrite is by far the most common and the most often mistaken for gold. Whether it is the golden look or something else, pyrite is a favorite among rock collectors. It can have a beautiful luster and interesting crystals. It is so common in the earth's crust that it is found in almost every possible environment, hence it has a vast number of forms and varieties.

Unlike gold, which is prized because of its color, brightness, workability, and rareness, Pyrite is not a metal, but rather, a sulfide made up of 46% iron and 54% sulfur. Pyrite is much harder and more brittle, and it tarnishes to a dark brown. Fool's Gold is very common, and this has led to many people thinking they had discovered real gold over the years. Pyrite forms when hydrogen sulfide combines with iron. These common elements often fuse and are carried by heated fluids to cracks in native rocks where pyrite is deposited. It is attractive, and many museums keep specimens of Pyrite for display or educational purposes.

Bravoite is the name given to a nickel-rich iron sulfide. It is closely related to pyrite but contains up to 20% nickel. Some mineral books treat it as a variety of pyrite. Pyrite is a polymorph of Marcasite, which means that it has the same chemistry, FeS2, as Marcasite; but a different structure and therefore different symmetry and crystal shapes. Pyrite is difficult to distinguish from Marcasite when a lack of clear indicators exists.

Common Shapes of Pyrite

Pyrite comes in many different shapes and forms. Most Pyrite that is mined consists of masses containing small crystals ranging from grains of sand size to a few mm and comprises about 70% of what is mined. This 70 percent is not considered to be collectible quality. The remaining 30% or so ranges from low grade collectible to good grade collectibles. There are very few fine grade minerals found in pyrite mines and they are usually found in small pockets.

Pyrite is found inclusive in many other minerals such as Serpentine, Rhodonite, Black Jade, Basalt, Quartz, Amethyst and Lapis Lazuli just to name a few. It is also found as Pyrite Suns from Sparta, Illinois. Pure Pyrite crystallization with no matrix featuring radiating golden crystals that sparkle in the light. These are also known as Pyrite Dollars and Sun Dollars. Collected in a coal mine hundreds of feet below the earth's surface, this sun formed over 300 million years ago! Fanned crystal structure is due to compressed growth between sheets of slate. Other forms may be like globular spheres that when split open have the same radiating outward lines as many pyrite suns.

Pyrite Crystals

Pyrite crystals are natural formatinns that occur in Geometric shapes. Their are three main shapes of pyrite crystals.

  1. Cube
  2. Pyritohedron
  3. Octahedron
Cube
Cube
Pyritohedron
Pyritohedron
Octahedron
Octahedron

Cube Pyrite These are the most common forms of pyrite crystals. They may look like squares but they are more correctly called Cuboids. (They are actually 3D rectangles. The term “3D rectangle” isn’t often used in formal geometric contexts, but it’s typically understood to mean a rectangular prism or cuboid.) These may look to be square, but if you measure the sides you will find they are actually rectangular.

Pyritohedral Pyrite These are less common than the cuboids. These crystals look like a sphere with many flat sides. These are sometimes referred to as dodecohedral pyrite specimens.

Octahedral Pyrite These are the rarest crystal forms of pyrite crystals.  They look like two pyramids with their bases joined together.

When viewing the many specimens of pyrite you will soon realize that there are many more variations to the shapes of pyrite crystals. When there are multiple crystals on a specimen it is called a crystal cluster. You will find that as these pyrite crystals form, sometimes they are not sure exactly what shape they will become. Some merge shapes in a process called intermediary combinations. This occurs when two or more shapes may be formed together, such as octahedral and cube or cube and pyritohedral or any other combination. These specimens are called complex combinations or complex alterations. In Peru 26 different intermediary shapes have been identified.

Below are some photos of the many variations of Pyrite

The bottom of many specimens ahve what is called a "breakaway surface" (or break surface). This surface is where the specimen was originally connected to its main matrix. If a specimen was recently broken off or even naturally fell off the pyrite will have very little luster and appear dull looking. If, on the other hand the specimen fell off naturally and layed there for a long period of time the pyrite begins to recrystallize anf the area becomes very shiney. Many Times jewelers use these recrystallized areas for making jewelry pieces.

 

Breakaway Pyrite 2
Breakaway Pyrite 2
Breakaway Pyrite 1
Breakaway Pyrite 1
Recrystallized back of Specimen
Recrystallized back of Specimen
Recrystallized Breakaway Pyrite 1
Recrystallized Breakaway Pyrite 1
Calcite Bulgaria (7)
Calcite Bulgaria (8)
Calcite Pyrite (2)
Calcite Pyrite (1)
Calcite Pyrite (5)
Calcite Pyrite (4)
Calcite Pyrite (6)
Calcite Pyrite (7)
Calcite Bulgaria (7) Calcite Bulgaria (8) Calcite Pyrite (2) Calcite Pyrite (1) Calcite Pyrite (5) Calcite Pyrite (4) Calcite Pyrite (6) Calcite Pyrite (7)
Item # 3PYR11215667

Calcite with Sphalerite inclusions and Pyrite from Bulgaria

$169.00

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This captivating specimen is from the Deveti Septemvri Mine, Madan ore field, Rhodope Mts, Smolyan Oblast, Bulgaria

Very rare specimen of pyrite on a Unique Calcite formation that has inclusions of Sphalerite. This for sure is a "One of a Kind" specimen from the mountains in Bulgaria. Striations of Sphalerite can be seen in the Calcite crystal blades.

This piece weighs 4.54 oz or 0.28 lb (129g) and measures 3.6 x 2.1 x 1 inches (9.2 x 5.3 x 2.6 cm).

Striated Pyrite 2 (4)
Striated Pyrite 2 (1)
Striated Pyrite 2 (2)
Striated Pyrite 2 (3)
Striated Pyrite 2 (5)
Striated Pyrite 2 (4) Striated Pyrite 2 (1) Striated Pyrite 2 (2) Striated Pyrite 2 (3) Striated Pyrite 2 (5)
Item # 2PYR11212972

Striated Pyrite with Black Sphalerite from Peru

$67.00

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Here's beautiful rare specimen of Striated Pyrite Cubes with asthetic formations of accenting Black Sphalerite. This stunning showpiece is from the Huanzala Mine, Haullanca, Bologesi, Ancash, Peru

This specimen weighs 2.4 oz or 0.15 lbs (70g) and measures 1.9 x 1.24 x 0.96 inches (4.8 x 3.2 x 2.4 cm)

Pyrite Sphalerite & Quartz 1 (3)
Pyrite Sphalerite & Quartz 1 (4)
Pyrite Sphalerite & Quartz 1 (5)
Pyrite Sphalerite & Quartz 1 (1)
Pyrite Sphalerite & Quartz 1 (2)
Pyrite Sphalerite & Quartz 1 (6)
Pyrite Sphalerite & Quartz 1 (3) Pyrite Sphalerite & Quartz 1 (4) Pyrite Sphalerite & Quartz 1 (5) Pyrite Sphalerite & Quartz 1 (1) Pyrite Sphalerite & Quartz 1 (2) Pyrite Sphalerite & Quartz 1 (6)
Item #3PYR11210613

Octahedral Pyrite Cluster with Black Sphalerite and White Quartz from Peru

$65.00

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Here's beautiful rare specimen of Octahedral Pyrite Crystals with a face covering of accenting Black Sphalerite and intermixed white Quartz. This stunning showpiece is from the Huanzala Mine, Haullanca, Bologesi, Ancash, Peru

This specimen weighs 1.86 oz or 0.11 lbs (53g) and measures 1.4 x 1.3 x 0.89 inches (3.6 x 3.4 x 2.3 cm)