The California Gold Rush (1849 – 1855) in the Sierra Nevada Mountains brought an economic revolution in California and the rest of the US. Boom cities grew, and the gold economic revolution became a global phenomenon. Today, the search for gold continues, but it has also drawn attention to pyrite (fool’s gold).
Gold and pyrite can be found together because they tend to be deposited in the same place simultaneously. Sometimes, gold deposits are located within the pyrite. When searching for gold, coming across pyrite is often a sign that gold and other minerals are present.
In this article, I’ll discuss gold and pyrite and why they occur in the same places. I’ll also analyze the differences between the two and why pyrite is often mistaken for gold.
Why Does Pyrite Form With Gold?
Over the years, gold collectors have developed ways to identify areas where gold deposits are most likely to be found. One indicator they look out for is pyrite deposits. The Carlin mines in Nevada are examples of regions where large deposits of gold and pyrite are present.
Pyrite forms with gold because hydrothermal fluids (mineral-rich water in the earth) move gold and pyrite and deposit them in rock crevices. Additionally, when pyrite crystals form, they develop tiny, imperfect crystal structures containing gold deposits within and around the pyrite structures.
It’s common to find different mineral deposits in the same area. Pyrite and gold share similar physical attributes, and to the naked eye, it’s easy to confuse one with the other. The fact that pyrite and gold crystalize together further complicates things.
Geological Signs Showing the Presence of Gold and Pyrite
Professional prospectors often point to the presence of gold and pyrite whenever they notice some telltale signs. While most use metal detectors, they look at natural features before searching for gold and pyrite.
Some geological features to look for when searching for gold and pyrite include:
- Iron-stained rocks.
- Quartz veins with rich colors and yellow blobs, and string-like features. This is a sign of heavy mineralization.
- Beached rocks. When rock outcrops take on a different color from the parent rock, this is a sign it may be heavily mineralized, and chemical reactions are causing the rocks to change color. Pyrite is an iron sulfide that aids in rock corrosion and bleaching.
If the area has historically been rich in gold and pyrite, you will likely find the two in the rocks and along the rivers.
Pyrite vs. Gold – How To Tell the Difference
Pyrite is known as fool’s gold because many people easily get fooled into believing it’s real gold. Even early miners and explorers, like Sir Martin Frobisher and Christopher Newport, saw the sparkly crystal and thought it was gold.
Fortunately, gold collectors understand how easy it’s to confuse pyrite for gold. So, they have found ways to differentiate pyrite from gold. You can identify the differences by the following features:
|It’s hard and rated at 6.5 – 7.0 on the Mohs scale.||It isn’t as hard as pyrite and is rated 2.5 – 3.0 on the Mohs scale.|
|Has a brassy appearance with greenish-black streaks.||Gold is bright yellow.|
|Pyrite is less dense than gold, with a 4.8 grams (0.17oz) density per cubic centimeter.||It’s quite dense (19.3g/0.68oz per cubic centimeter).|
|It shines more than gold.||It shines but isn’t as shiny as pyrite.|
|When hit with a hammer, it turns into dust, but sometimes it resists pressure.||Gold remains solid when hit by a hammer but takes on different shapes.|
|Not malleable.||Malleable into various shapes.|
|Typically appears in geometric shapes.||It doesn’t occur in regular shapes but appears as roundish globes or flakes.|
|When rubbed against a rough surface, it smells like sulfur.||It has no odor.|
|It leaves a black or dark green streak when scraped on unglazed porcelain.||It leaves a gold-yellow streak when rubbed on unglazed porcelain.|
To learn more about differentiating gold and pyrite, watch this video by Ask Jeff Williams.
Similarities Between Gold and Pyrite
The primary reason gold and pyrite are easily confused is that they are similar in color. Both minerals appear yellow and shiny, but they have different color tones. Pyrite is more brassy than gold.
Unfortunately, their color is the only way to tell gold apart from pyrite with the naked eye. Unless you perform mineral tests, you can easily mistake pyrite for gold and pay a higher price if you don’t do thorough checks.
How To Separate Gold From Pyrite
Since gold and pyrite tend to form together, gold collectors must separate them. Sometimes, gold is hidden within the pyrite, and it takes some work to separate and get to the precious metal. In nature, the oxidization process wears down the pyrite, exposing the gold.
The two main ways gold collectors extract gold from pyrite are gravity separation and floatation separation.
This is the most common separation method for getting gold from pyrite. It’s ideal when working with coarse pyrite pieces because it’s energy efficient and quite effective at getting gold from pyrite. It also requires less investment.
The process involves crushing, grinding, and separating gold from pyrite. Since gold is denser than pyrite, it will settle at the bottom of the pan. The downside is that even though this method is cheaper, you may eventually miss some gold pieces in the process.
Like gravity separation, the floatation method involves crushing and grinding pyrite. However, the difference is it involves a larger investment in equipment use. It’s also more efficient because the chances of losing gold in pyrite are minimal.
Since the pyrite is wholly crushed, this method is also ideal for low-grade pyrite that won’t be useful after the gold is extracted.
The Value of Pyrite vs. Gold
Pyrite earned the title fool’s gold because this mineral once fooled many people into believing it was gold. However, the greatest deception wasn’t in what it was but in its value. When explorers attempted to conquer the new world, they focused on finding valuable land.
The primary focus was gold and its value. So, explorers were disappointed when they discovered that all they got from their voyages were pyrite.
Pyrite has some commercial value today, but it’s far from the higher price of raw gold.
The value of pyrite varies, depending on the form.
|Pyrite Form||Average Price|
|Raw Pyrite.||$0.03 – 0.05 per carat.|
|Pyrite nuggets.||$20 per pound (0.5kg)|
|Pyrite gemstone.||$5 – $8 per carat.|
|Pyrite specimen.||$3 – $ 0.65 per carat.|
Just like gold, the price of pyrite depends on its form, supply, and demand. Pyrite with traces of gold usually costs much more than plain pyrite. Some buyers pay up to $1,500 per troy ounce (31.10 grams) for samples containing 0.25% gold.
The value of gold has been relatively high since its discovery. However, in the 1800s, gold was more abundant, so it fluctuated between $400 and $600. The value peaked at $2,600 per ounce (28 grams) in 1980.
In 2001, the price per ounce of gold dropped drastically to $450. Since then, the price has risen steadily to $1,928 per ounce (28 grams) today.
Uses of Pyrite
When prospectors find gold, they often already have a plan for what to do with it. Some may add the pieces to their collection until they have collected a significant amount for selling. Gold nuggets sell much faster and at a better price than small gold pieces.
Jewelers are always ready to buy gold. The challenge comes when you have pyrite. Pyrite has value in the market, but it may take more research to find willing buyers. Fortunately, pyrite has its uses.
- Sulfuric acid comes from pyrite. Sulfuric acid is used to produce fertilizer, car batteries, and cleaning agents.
- Roasting pyrite produces sulfur dioxide. This gas is used to make paper and is sometimes used in food preservatives.
- Pyrite occurring with other minerals will have a higher value. Pyrite formations that contain cobalt, gold, and silver attract a higher price.
- The pyrite gemstone is used for making jewelry. Pyrite’s natural abundance makes it an affordable stone for jewelry. However, jewelers must be careful when cutting it due to its brittleness.
- In Feng Shui, pyrite is believed to attract wealth and abundance. You can place a pyrite stone in your home for prosperity.
You can find pyrite and gold together in several instances because they naturally occur together. However, you can only be sure the yellow spots in quartz or other rocks are gold or pyrite through mineral tests. Fortunately, the differences are evident when you know how to tell them apart.