Tunney’s Pasture sounds peaceful, but the name hides one of the most unusual sources of uranium-bearing rock in Canada. The federal government complex in Ottawa once housed an experimental SLOWPOKE reactor and other Cold War science facilities. This is not a mining district. It is not a place collectors can visit. Whatever material exists from the research era is scattered, buried, paved over, or forgotten.

Yet one of those pieces survived long enough to be dug up, cut open, polished, and is now placed on my workbench with a future very different from its past.

This polished slab of uraninite from Tunney’s Pasture has big plans.

Field Discovery by Jonathan Bélanger

The story begins with a Reddit reply. After I posted an early photo of this slab, a collector named Jonathan Bélanger reached out and said the words every mineral writer dreams of hearing.

“I am the guy who dug out the rock that was used for the slab.”

Jonathan explained that he had been exploring the wooded strips beside the Tunney’s Pasture complex after watching videos of people hunting radioactive rocks. The moment he realized the old SLOWPOKE reactor site was nearby, he grabbed his Radiacode, mounted it on a GoPro selfie stick, and set out to investigate.

Within twenty minutes, he found the hotspot.

The discovery zone is small, about 300 feet by 100 feet, and looks disturbed. The soil sits unevenly. Heavy dark stones are scattered in clusters. It resembles a dumping area near the old reactor footprint rather than natural geology.

Jonathan dug directly into that spot and pulled out several uranium-rich rocks, including the one that eventually became this slab.

https://imgur.com/a/XVsJ4fJ

He later shared a second video of his hands-free search of the area, showing his field method and additional finds.

 https://imgur.com/a/u8DylA5

His haul photo shows multiple pieces of interest. He believes the rock closest to the camera is the parent piece.

His field setup is simple and effective. Radiacode attached to a GoPro selfie stick for hands-free scanning.

Jonathan gave full permission to credit him by name, and his discovery adds scientific value to the slab. Provenance matters, especially when navigating Cold War-era material with no formal mineral locality in the usual sense.

From Field Rock to Scientific Slab

Once Jonathan recovered the stone, it was sent to the team at RadioactiveRock.com, where it was cut and professionally polished. The original surface was weathered and rough. The interior was something else entirely.

Polishing revealed a clear cross-section of uraninite-rich veins, oxidation halos, and fracture geometry. This type of clarity is almost impossible to see in uncut ore.

Inside the slab, you can identify:

• Black metallic uraninite

• Red and orange oxidation fronts

• Microfractures shaped by heat and long-term radiation

• Subtle zones where uranium migrated during weathering

This is not mine run ore. It is a research-adjacent artifact with geological and historical significance, revealed through precise cutting and polishing.

Radiation Readings and What They Tell Us

Pressed directly against the polished surface, a Radiacode 103 registers 656 CPS. That value fits the profile of uraninite in matrix with moderate alteration. The slab's geometry allows radiation to reach the detector efficiently, often yielding cleaner numbers than rough material.

The reading confirms:

• This is true uraninite

• It has undergone oxidative alteration

• It is strong but not in the extreme metamict range

• It is safe to handle with proper storage and standard precautions

It is always satisfying when the detector and the geology agree.

Cold War Context and Why This Material Exists at All

Tunney’s Pasture is not a mineral locality in the traditional sense. It is a government research campus. The SLOWPOKE reactor operated there in the mid twentieth century, along with other scientific facilities. Over the decades, the landscape changed, buildings were added or demolished, and ground materials were moved or redistributed during construction.

That history explains why heavy, uranium-rich rocks appear in a narrow, disturbed zone beside the old reactor footprint. The material was not mined there. It was placed there, intentionally or unintentionally, during years of scientific activity and site modification.

This gives the slab a hybrid identity.

It is part geology. Part research artifact.Part Cold War history.

Few specimens carry that blend.

Big Plans for a Polished Slab

The slab is not a belt buckle yet, but that is the plan. It has the structure, stability, and visual impact that make it perfect for wearable radioactive art.

When framed in metal, the black uraninite veins will create strong directional lines. The oxidation halos will act as a warm contrast. The fracture network will add visual depth. Once mounted to a backing plate and sealed, it will be stable, durable, and absolutely impossible to ignore.

Radiation dose is not a concern when worn over clothing. You will absorb far more on a cross-country flight. The absolute joy of the buckle will be the quiet chirp of a detector held near it, which is precisely the kind of chaos that makes mineral collecting fun.

This slab has traveled far already:

• Dug up by Jonathan in Ottawa

• Cut and polished by RadioactiveRock.com

• Now sitting on my workbench

• Soon to be wearable science

Its next life will be loud in the best possible way.

Up Next

Next, I will cover my Markey Mine specimen and explain how uranium silicates produce some of the brightest UV fluorescent responses in the United States.

Stay curious, stay safe, and keep your detectors chirping.