Chasing the Color Blue: A Journey into Norway’s Cobalt Mines
- Asia Zięba-Rusevicius
- May 26
- 4 min read
There’s something about the color blue—it pulls you in. From open skies to deep oceans, it sparks a quiet curiosity. Among all its shades, cobalt blue stands out with its intense, bold tone. This beautiful pigment, made from the mineral cobalt, has been treasured for centuries in art, ceramics, and glassmaking.
That deep, cool hue inspired us to visit the Cobalt Works Museum (Blaafarveværket) in Modum, just 80 km from Oslo. On a rainy morning, we set out to uncover the story behind cobalt blue—right where it was once mined.
Setting the Scene: Into the Mountains of Modum
As we drove through the mist and steady rain, the Norwegian landscape revealed its rugged charm—green hills, bare rock faces, and low-hanging clouds.
The Modum region was once home to one of Europe’s most important cobalt mining operations.
Our destination: the old mines of Blaafarveværket, once Norway’s largest employer in the 1840s.
Entering the Mines: The Heart of Cobalt Blue
At the mine entrance "Clara", the cold hit instantly—around 6°C all year. As we ventured underground, helmets on , we explored 1.5 km into the mountainside. The tour winds through steep ladders, narrow passages, and damp rock walls, making it part hike, part time travel.
Why It Matters
Cobalt isn’t just known for its beautiful blue color—it also plays a big role in our everyday lives. It’s a key ingredient in batteries for electric cars and is super important for keeping our electronics running smoothly.
What’s fascinated us, both now and in the past, is how this dull grey ore transforms into such a vibrant blue. It’s the same mineral that’s been used for centuries to create blue pigment, even making its way to China and other parts of the world.
Adventures in the Cave: Discovering the Colors of Cobalt
Alright, let’s be honest—you won’t stumble upon any jaw-dropping displays of cobalt blue in its raw form. Sorry to disappoint! 😄
Identifying cobalt in nature isn’t as flashy as you might hope. Instead, it usually shows up alongside two eye-catching minerals: the green veins of malachite and the vibrant pink streaks of erythrite (https://snl.no/erytrin) also known as “red cobalt.”
Continuing the Exploration of Cobalt Blue
Blue pigments can be either natural or synthetic, and have traditionally been made from mineral sources such as lapis lazuli, azurite, and cobalt compounds.
When heated to about 1200°C with alumina, cobalt transforms into a rich blue pigment. That process, called sintering, was first used in 1803 to create synthetic cobalt blue as a cheaper alternative to ultramarine.
Another early cobalt pigment is smalt, a blue potassium glass ground into powder. It was used by painters in the 16th and 17th centuries—especially by Dutch and Flemish artists.
There’s a clear difference between the two pigments: smalt has reddish undertones and leans closer to synthetic ultramarine, while cobalt blue is cooler and more closely resembles the deep, richer, warmer tones of lapis lazuli - natural ultramarine.
At the museum, rows of glass jars display compounds and minerals and found during mining—including pure cobalt pigment (results), a stunning, deep blue powder.
A Glimpse into the Past
Long before modern science gave cobalt its name,
as early as 2600 BC,
the ancient Egyptians and distant civilizations
were already capturing the sky in their hands
crafting glassware, glazes, and ceramic.
With a blue so deep,
it seemed plucked from the heavens.
Centuries later,
the same hue found its way into Chinese porcelain,
rich and clouded with the mystery of impure cobalt.
Then in 1742, Swedish chemist Georg Brandt
pulled back the veil of alchemy
and revealed cobalt as the hidden source of this blue magic—
a metal, once unknown, now eternal in name.
By 1777, “cobalt blue” had entered the English tongue,
and in 1802, French chemist Louis Jacques Thénard refined it further—
creating a purer, alumina-based pigment, that would soon dance on canvases and porcelain alike.
By 1807, France was turning fire into color, and in the century that followed,a quiet valley in Norway becamethe heart of the world's cobalt blue.
Blaafarveværket—the “Blue Color Works”—founded in 1776 by King Christian VII,
was tasked with coloring the future.
Its pigment—cobalt zinc silicate—gave Royal Copenhagen porcelain its iconic hue.
For more than 100 years, Modum's cobalt stained the world in beauty,
filling glass and porcelain with a brillianceborn deep underground.
Mining ceased in 1898, but the story lingers in the hills.
Today Blaafarveværket stands not as a factory, but as a memory—a meeting place of nature, science, and art,where the earth once whispered in blue.
Final Thoughts
The tour left us cold, a little muddy, but deeply inspired. The vibrant blue that once captured the imagination of artists still lies beneath the surface—quietly waiting to tell its story.
(Next time, we’re bringing a UV flashlight—some minerals glow under 365 nm light. Already packed!)