What Are Montana Sapphires?

The Rocky Mountains and the Great Plains set the stage for the wild and wide-open beauty and evergreen landscapes rolling across Montana, The Treasure State. And in Big Sky Country, treasure is exactly what you’ll find in the form of glittering Montana Sapphires. 

It’s no surprise that one of the U.S.’ most breathtaking states–home of jaw-dropping mountains and a stretch of Yellowstone National Park–is a hotbed for colorful sapphires.

Echoing the grandeur of the open sky and rolling plains, Montana sapphires bedazzle in shades of blue, yellow and pink. 

So, what is a Montana Sapphire and why are there so many of them in Montana?

History and Origins of Montana Sapphires

What makes Montana Sapphires unique is that despite these gemstones being available worldwide, from Australia to Nepal, Montana sapphires are an ethical, high-quality gemstone hailing only from North America. In the U.S., Montana is the only state to commercially mine sapphires.

So, we know Montana sapphires come from Montana, but which deposits yield Montana Sapphires?

Montana Sapphires are primarily mined from the Missouri River, Rock Creek (also known as Gem Mountain), and Dry Cottonwood Creek. 

During the Montana Gold Rush in the late 1800s, prospectors flocked west in search of gold. What they found in Montana, however, was a pale, steely colored gemstone that plugged their pans and got in the way of their gold. Of little value to them at the time, miners chucked them away or chipped them down with iron scraps to be sold to watch traders.

Now, these sapphire deposits located in Montana’s rich gem-producing land are the leading source of sapphires in the United States. It is unclear exactly why the geology in these locations produces sapphires. Some allege that streams carried the sapphires from the mountains into the river’s gravel. Others believe the sapphires traveled to Montana by glaciers. 

Regardless of how the sapphires got to Montana, one thing’s for sure: miner’s know better than to toss them aside now.

What Are Yogo Sapphires?

In Montana, there is a region of land called Yogo Gulch where sapphires form in the igneous rock. Rather than having to sift through gravel and sediments in the riverbed, miners produced sapphires straight at the source. Yogo Sapphires are generally quite small, and occur naturally in a medium-to-light shade of cornflower blue. What differentiates Yogo sapphires from traditional Montana sapphires is that they are a fraction smaller, weighing commonly less than half a carat. Additionally, they’re void of the green hue found in Montana Sapphires and don’t have the same color zoning, either. 

The Yogo Gulch mine has since closed, making these sapphires a highly valued novelty, essentially, they are expensive because of their rarity.

Montana Sapphire - Yogo

Are Montana Sapphires Ethical?

Mining guidelines and regulations in the United States are strict, making Montana sapphires a more ethical gemstone than others. Namely because mining procedures have a less harsh effect on the Earth, as they are collected from the river.

Instead of digging into the Earth to access gemstone deposits, Montana sapphires are naturally weathered and mined via an alluvial deposit. Basically, when the host rock is exposed to the natural elements, the stone breaks up and when it rains, water carries the sapphires to rivers, lakes, and streams.

After the sapphires are mined, the gemstones are treated and faceted locally, minimizing the environmental impact by eliminating air travel and carbon emissions.

Montana Sapphire Durability

All sapphires are highly durable and scratch resistant, and Montana sapphires are no different. They make perfect gemstones for daily wear as they’re extremely tough, with a hardness of 9 on the Mohs scale. In fact, sapphires are second only to diamonds in terms of strength and durability, so you’ll have peace of mind knowing they are going to last a lifetime.

Montana Sapphire
Rough Montana Sapphire

Are Montana Sapphires Valuable?

The same process used to determine the value of a diamond, the 4Cs, is also used to evaluate the worth of a Montana sapphire. Below are important things to know about the color, clarity, cut and carat of Montana sapphires.

What Colors Are Montana Sapphires?

Most people love sapphires for their deeply saturated, clear blue color. However, sapphires are a gemstone that naturally occurs in a rainbow of colors, excluding red. A red sapphire is actually a ruby. 

Montana Sapphires come in various hues, including blue, pink and yellow. While these stones have a unique beauty, they are naturally quite steely, and don’t have the brilliant color we value in gemstones. That’s why Montana sapphires require treatment to improve color. 

Surprisingly, less than 15% of Montana sapphires occur naturally colorful. Otherwise, they are predominantly blue with a hint of green and gray. To enhance the color spectrum of these hard gemstones and make them suitable for jewelry, heat treatment is applied.

Initially, these stones are pale and slightly green. Heat allows the stone to continue on its journey to becoming the beautiful gemstone it is meant to be. While this is technically an alteration to the natural stone, heat alone is used without the aid of chemicals or additives, and is a gentle way of color-treating sapphires. 

Color plays an important role in valuing Montana sapphires, and these gorgeous gemstones have a unique way of shifting shades under certain lighting. 


Clarity, Cut and Carat

Montana sapphires have minimal inclusions and great clarity. In fact, any inclusions occur within the rutile needles and are not visible to the eye.

Just like diamonds, Montana sapphires are cut into the most popular shapes including round brilliant, princess cut, oval and pear. Most commonly, Montana sapphires weigh .5-1 carat. While there are larger carats, they are quite rare and expensive. It’s extremely uncommon to find a Montana sapphire over 6 mm.

Of all the qualities of a sapphire gemstone, color tends to be the most important factor when pricing a sapphire. After all, who doesn’t love a fiery sapphire?

Ready to find your gem from The Treasure State? Browse our collection of Montana sapphires.




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