Hunting for diamonds in New Jersey might sound like a dream, but it’s possible with a little patience and the right spots. From popular places like the Franklin Mineral Museum to hidden treasures like the Raritan River, the state is full of opportunities to find dazzling stones.

This guide highlights some of the best locations to search for diamonds and other valuable finds. It also shares tips and interesting facts about each spot, making it easy to start an exciting adventure in New Jersey.

How Diamond Forms Here

Diamonds form deep within the Earth, about 90 to 200 kilometers below the surface, where conditions are extreme.

Here, carbon atoms are subjected to intense heat—around 900 to 1,300 degrees Celsius—and immense pressure, about 45 to 60 kilobars. This environment causes the carbon to crystallize into diamond structures over millions to billions of years.

Over time, erosion and weathering expose these stones, making them accessible for mining.

What’s amazing is that each diamond’s journey from deep within the Earth makes it unique, with its own shape, size, and clarity.

The Types of Diamond

Diamonds are classified into various types based on their structure and color. Here are some of the popular types of diamond:

Black Diamond

Black diamonds, also known as carbonados, are truly one-of-a-kind. Unlike their clear cousins, these stones are opaque and have a matte finish.

They don’t sparkle in the traditional sense but have a unique, mysterious charm all their own.

What makes black diamonds special is their age and formation. Most are believed to be 2.6 to 3.2 billion years old, making them some of the oldest gemstones on Earth.

Their dark color comes from numerous inclusions and the presence of graphite or other minerals.

Recently, a massive black diamond called “The Enigma” made headlines. Weighing 555.55 carats, it showcases the growing interest in these unusual stones.

Yellow Diamond

Yellow diamonds shine with a vibrant, sunny hue. Their color ranges from light yellow to deep, intense shades.

This beautiful color comes from nitrogen atoms in the diamond’s structure. These atoms absorb blue light and reflect yellow, giving the stone its unique appearance.

Unlike clear diamonds, yellow diamonds are graded based on their color intensity. The deeper and richer the yellow, the more valuable the stone. This grading system is different from the one used for colorless diamonds.

Blue Diamond

The color of the blue diamond can range from a soft, icy blue to a deep, vivid shade. This striking blue comes from boron in the diamond’s crystal structure. It’s a rare occurrence in nature, making these diamonds very uncommon.

One cool thing about blue diamonds is how they react to ultraviolet light. Many of them show a unique glow called fluorescence. This can make their color even more impressive under certain lighting.

Blue diamonds have some famous examples. The Hope Diamond is probably the most well-known. It’s known for being the largest diamond weighing 45.52 carats. It’s current value is estimated to be US$200–350 million.

Red Diamond

Red diamonds are incredibly rare and highly prized. Their distinct red color comes from structural imperfections in the diamond’s crystal lattice, not from chemical impurities like other colored diamonds.

These diamonds are so rare that very few have ever been found. Each discovery of a red diamond is a significant event in the gemstone world.

Their rarity makes them even more valuable than pink or blue diamonds, which are already considered extremely precious.

Some famous red diamonds have captured public attention. The Moussaieff Red from Brazil and the Kazanjian Red Diamond from South Africa are notable examples.

In 1987, a red diamond (Hancock Diamond) sold at auction for a record-setting $927,000, highlighting the extraordinary value placed on these rare gems.

Pink Diamond

Pink diamond’s color can be a soft, delicate pink or a deep, vivid rose. What’s interesting is that scientists aren’t entirely sure why they’re pink. It’s thought to be due to a twist in their crystal structure, not because of any specific element.

These diamonds are incredibly scarce. For every million carats of rough diamonds mined, only one carat might be a pink diamond. This rarity makes them highly prized by collectors and jewelers.

Even small pink diamonds can be worth a lot because of their rarity. They’re often used in high-end jewelry, where their unique color makes a big impact.

Green Diamond

Green diamonds are some of the most unusual and unique colored diamonds. Their color can range from a light mint to a deep forest green

What makes them special is how they get their color. It’s not from a chemical element, but from exposure to natural radiation over millions of years.

This natural coloring process is incredible. It happens when diamonds are near radioactive rocks deep in the earth. The radiation changes the diamond’s crystal structure, creating the green color.

Green diamonds often show unique light effects. Some might have a strong glow under certain lights, adding to their allure.

What Rough Diamonds Look Like

Rough diamonds can be challenging to identify. Here are a few proven techniques that will make it easier for you to identify the rough diamond:

Check for a Glassy or Waxy Luster

One of the most noticeable features of a rough diamond is its luster. Uncut diamonds often have a glassy or waxy appearance.

This is because the rough surface scatters light differently than a smooth, cut surface.

Look for an Octahedral Shape

Rough diamonds typically take on an octahedral shape, which resembles two pyramids joined at the base. This shape is a result of the diamond’s cubic crystal structure.

However, not all rough diamonds will have a perfect octahedral form, as they can be distorted or irregular due to natural forces during formation.

Assess the Density and Weight

Diamonds are known for their density and weight. A rough diamond will feel heavy for its size compared to other stones.

You can test this by holding the stone in your hand and comparing it to a known non-diamond.

Look for a Crystalline Texture

When examining a rough diamond, you may notice a distinct crystalline texture on its surface.

This is due to the diamond’s atomic structure and can help distinguish it from other minerals or synthetic stones.

A Quick Request About Collecting

Tips on where to look

Once you get to the places we have listed below there are some things you should keep in mind when you’re searching:

Look in Sedimentary Rocks

Sedimentary rocks are a great place to start. These rocks form from layers of materials that have settled over time.

Diamonds can be found in these layers. Look for areas where the rock has been worn down or eroded. This is where diamonds might be exposed.

Explore Riverbeds

Rivers are another excellent spot. Over time, water carries diamonds downstream. Look for gravel beds in rivers. These spots can hold diamonds that have been washed away from their original location.

Pay attention to bends in the river. These areas often collect heavier materials, including diamonds.

Check Old Mining Sites

Old mining sites are worth exploring. Many diamonds were left behind during past mining activities.

Look for areas where mining was done in the past. Even if the site is no longer active, it can still be a good place to find hidden gems.

Investigate Hillsides

Hillsides can also be promising. Erosion can expose diamond-bearing rocks. Look for loose soil or rock on slopes.

These areas may reveal diamonds that have been pushed to the surface over time.

The types of Diamond you can find around the state

New Jersey is home to unique diamonds, each with its own special qualities. Black diamonds stand out with their dark, matte finish and mysterious charm, shaped by inclusions and graphite over billions of years.

Yellow diamonds sparkle with a bright hue from nitrogen atoms, while green diamonds owe their rare color to natural radiation. When searching, watch for rough stones with a glassy luster, octahedral shapes, or crystalline textures—they might just lead to an incredible discovery!

Some Great Places To Start

Here are some of the better places in the state to start looking:

Chimney Rock Quarry

Chimney Rock Quarry in New Jersey is a great spot for those searching for diamonds and minerals. The quarry is known for its rich geology, making it a perfect place to look for rough diamonds, although they are not commonly found.

For the best chances of success, focus on areas where the rock layers have been disturbed, especially near the edges of the quarry. Keep an eye out for stones that have a glassy or waxy luster and look for octahedral shapes, which are often seen in rough diamonds.

Mount Hope Mine

Mount Hope Mine is an exciting spot for anyone searching for diamonds in New Jersey. With its history of mineral mining, the area holds plenty of geological treasures, and while actual diamonds are rare, it’s possible to find stones that look similar to rough diamonds.

Many successful hunters check the ground right after rain washes away loose dirt, making crystals easier to spot. While you search, you might also find other cool minerals like garnets or pyrite that the miners left behind.

Oxford Mine

Oxford Mine is a great spot for rock collectors and those hoping to find diamonds in New Jersey. The mine is known for its rich mineral deposits, making it an exciting place to search for rare stones, including those that might look like rough diamonds.

The mine’s mineral-rich quartz veins create perfect pockets where crystals form. Search near the old mining equipment and tailings piles, where decades of digging brought deep minerals to the surface. Amateur geologists often have luck in the spring when melting snow exposes fresh material.

Califon region

The Califon region in New Jersey is a great spot for those eager to search for diamonds. Known for its rich mineral deposits, the area is a popular destination for rock collectors and diamond hunters alike.

The best places to look are where streams meet bigger creeks, since fast water drops heavy stones there. Bring a plastic screen to shake out small rocks, and hunt after rain when the dirt has been washed away.

Demarest area

The Demarest area in New Jersey is an exciting place for those searching for diamonds. Known for its varied geological features, it offers a good chance to find rare minerals, including rough diamonds.

To increase the chances of a discovery, focus on loose soil or gravel, especially near old mining spots or riverbeds. Look for stones with a glassy texture and octahedral shapes, as these may be diamonds waiting to be found.

Places Diamond has been found by county