Pyrite, FeS2, can form in a variety of different geologic environments, though these environments must contain sulfur and iron. In sedimentary rock, pyrite is typically formed in oxygen-lacking environments as a byproduct of the decay process of organic matter. When the small amounts of oxygen are consumed during decay, sulfur is often a byproduct. When iron is present in this environment, pyrite has the chemical components to form. In marine shales around the world, small disk shaped pyrite formations are found as a result of this process. The coal deposits near Sparta, Illinois produce large pyrite disks that are known as "pyrite suns". In sedimentary deposits, pyrite is also found to have replaced organic matter of various organisms, known as pyritized fossils. This process, known as permineralization, requires both anaerobic (does not require oxygen for survival) and aerobic (needs oxygen) bacteria, as well as an oxygen-poor environment that provides the proper amount of iron. The organic matter consumption process of aerobic and anaerobic bacteria results in production of sulfide, which with the help of the bacteria, combines with the iron present in the environment and oxidizes. By this process, soft tissue has been found preserved as pyrite. An example of this is the pyritized trilobites that come out of the Whetstone Gulf Formation of New York. These trilobites have been found with phenomenal soft tissue preservation, including egg preservation.
Pyrite occurs all over the world, with thousands of known localities where well formed pyrite crystals can be found. However, some localities stand out more than others, whether it be because of the pyrite's crystal structure, color, or just the overall aesthetic appearance of it. One of these localities that produces phenomenal pyrite cubes is the Victoria Mine in Navajun, Spain. Pyrite from this location is famous for its beautiful luster, near-perfect cubic formation and sculptural appearance. The pyrite deposit of "Ampliación a Victoria" is located 3km northwest from Navajún town, in the Alcarama Mountain Chain. The history of mining in the area goes back to Romans mining for silver. Modern galena mining led to the discovery of the pyrite in 1965, and since then specimens from this locality have been sought out by collectors world wide. The largest crystal to date was over 19cm wide and weighed 9.5kg. Peru is known to be one country that produces an assortment of different pyrite formations from a variety of mines. The Huanzala Mine is one mine in Peru that is renowned for its pristine and beautiful pyrite crystals, as well as a wide variety of pyrite crystal structures. Pyritohedral, octahedral and cubic crystals have come out of this locality.
The United States has many different locations that produce remarkable pyrite specimens. One notable locality that is relatively close to us here at FossilEra is the Spruce Ridge Claim in King County, Washington. This area in the Cascade Mountain Range is known for its quartz and pyrite associations, many of which produce pyrite crystals that can be quite large and exhibit excellent luster. How Does Pyrite Differ From Gold?
To the untrained eye, pyrite looks very similar to gold, therefore it's easy to misidentify as gold. This predicament earned pyrite the alternative name of "fools gold". Gold and Pyrite are chemically different, resulting in different physical characteristics. For example, when applying pressure to pyrite, it will typically break or crumble, while gold will bend. The streak of pyrite is a brown-grey color while gold streaks a yellow color. Finding well formed crystals is indicative of a pyrite deposit, for gold rarely forms as faceted crystals. Also, the process of testing the streak of pyrite should release a sulfurous odor due to the sulfur content of pyrite, while gold shouldn't release any smell. That being said, pyrite and gold form in similar environments. In some cases, finding pyrite can be considered an indicator of possible nearby gold deposits.
What Is Pyrite Used For?
At one point in time, pyrite was a leading source of sulfur and sulfuric acid due to its sulfur content. However, obtaining sulfur from pyrite is a very uncommon practice nowadays for most sulfur is sourced from hydrodesulfurization (striping oil molecules of sulfur atoms) during crude oil processing. As far as iron is concerned, even though pyrite contains a sufficient concentration of iron, pyrite is not the leading source of iron production. Instead, hematite is the leading source of iron ore for economic reasons. Though if this source for whatever reason became absent, pyrite could take its place, along with some other iron-rich minerals. Overall, pyrite's modern day primary applications are in jewelry, as display pieces and as a minor source of gold. It has also become popular with the metaphysical and crystal healing community.
SOURCE: Leonskie
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