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What are Montana Sapphires?

Sarah O. Editorial Team | Updated 12 May 2025
Published 28 Oct 2024 | 5min read

Montana sapphires are as unique as the breathtaking landscapes they come from. Ethically sourced in Montana, these gemstones are known for their distinctive color range. They are highly durable, with a hardness of 9 on the Mohs scale. This makes them a stylish and durable alternative to the classic diamond engagement ring.

The range of colors available makes Montana sapphires perfect for non-traditional jewelry lovers. Each one-of-a-kind sapphire tells a story of American heritage and natural beauty, shaped over millions of years in the heart of Montana. Read on to learn more about these stunning stones.

Montana Sapphire Inventory

Montana sapphires are found in a wide array of rich and sparkling hues.

Montana Sapphire Colors

Montana sapphires range from deep blues, teals and greens to rare violet-pinks. These sapphires are also color shifters, meaning that the colors change with the light source.

So where does their unique color come from? Like all sapphires, Montana sapphires are varieties of the mineral corundum. The color of corundum is determined by trace elements within the stone. Montana is a region rich in iron, which causes the blue and green hues that Montana sapphires are known for.

These stones are ideal for jewelry that speaks to individual style, offering shades that are as unique as the person wearing them.

Sorting through rough Montana Sapphires

Montana sapphires are ethically sourced to preserve the beauty of nature.

Ethical and Sustainable Sourcing

Montana sapphires were originally discovered in the 1860s by gold rush prospectors. Today, many Montana sapphires are sourced with small-scale and artisanal mining practices, with an emphasis on minimizing environmental impact.

Most Montana sapphires are sourced from one of four locations: Rock Creek, Yogo Gulch, Dry Cottonwood Creek, and the Missouri River. Yogo Gulch sapphires are found in igneous bedrock, while other Montana sapphires are found in alluvial deposits—loose clay, silt, and sand deposited by running water.

At Sarah O., our sapphires are sourced from Rock Creek Mine, also known as Gem Mountain in Phillipsburg, Montana. Rock Creek is the largest sapphire mine in the world and known for its commitment to sustainability. Our team recently visited this site to see the ethical mining practices firsthand. After mining, they replace the soil and replant native vegetation, ensuring the land’s natural beauty is preserved.

Loose Montana Sapphires

Different gemstone cuts and faceting techniques bring the beauty of Montana sapphires to life.

Big Carat Montana Sapphires

One of the most exciting aspects of Montana sapphires is their rarity, especially when it comes to larger carat sizes. Big carat Montana sapphires are a collector’s dream, offering impact and unique beauty that’s hard to find elsewhere. At Sarah O., we pride ourselves on our collection of big carat Montana sapphires, allowing our clients to own truly unique and rare jewelry.

Bi Color Jenna Montana Sapphire

This engagement ring features an ocean-colored Montana sapphire encased in a gold bezel.

Montana Sapphire Buying Guide

With so much variance between different Montana sapphires, it can be overwhelming to determine the right stone for you. Here’s some factors to consider when shopping for Montana sapphire jewelry.

Inclusions

Many Montana sapphire contain internal inclusions—tiny imperfections within the stone. Inclusions can add a silky quality to the stone, but too many inclusions can inhibit light reflection and make the stone appear less brilliant. Consider what type of quality you’d like your sapphire to exhibit when shopping for stones with inclusions.

Montana Sapphire Ring in Rough

The unique peacock hue and color zoning makes this Montana sapphire a one-of-a-kind center stone.

Color

In addition to its wide range of hues, Montana sapphires can also exhibit specialty colors and effects. This includes parti-color sapphires, where more than one color is present within the stone. This multi-color quality is also referred to as “color zoning”. Parti-color sapphires have traditionally been less valuable, but are quickly rising in popularity. Multiple Montana sapphires with different hues can also be combined in one jewelry piece to create a stunning multi-color effect.

Carat Weight

Carat weight is a large factor in determining the value of a sapphire. One half-carat Montana sapphire might cost $400-700, while one-carat Montana sapphires might cost $1,500-$2,500. Two-carat stones might cost 2-3X the price of one-carat gems. Because big carat Montana sapphires are such a rare find, stones over three carats are highly valued and prized by collectors.

Heat Treatment

Like all sapphires, Montana sapphires can be heated or unheated. Many Montana sapphires are heated before polishing to improve the color and clarity. Some people prefer unheated stones because the natural color is unchanged, making unheated Montana sapphires prized by collectors.

Sarah O. Picks

Are you already enchanted by Montana sapphires? Start here with some of our favorite jewelry pieces that celebrate the unique natural beauty of these gemstones.

Celebrate your love with this gorgeous sea-green 1.09ct Montana sapphire.

The Nova Ring: $3,473

The Nova Ring features a stunning Montana sapphire surrounded by a starburst diamond halo. The star of this piece is the beautiful center stone, with hues as deep and alluring as the ocean.

Two stunning Montana sapphires combine in a toi e moi setting.

The Holland Ring: $5,985

This classic toi e moi setting is perfect for displaying the shade variation found in Montana sapphires. If you’re looking for a ring that represents you and your partner’s unique love story, look no further than the Holland Ring.

This showstopping piece features a 2.39ct cornflower blue Montana sapphire.

The Seine Ring: $11,525

Mirror, mirror, on the wall, who’s the fairest ring of all? The stunning Seine Ring features a round Montana sapphire with a mirror-bright polish you won’t be able to tear your eyes away from.

Bringing Montana’s Beauty to You

Montana sapphires are truly special gems, offering a one-of-a-kind beauty and a captivating range of colors. At Sarah O., we’re proud to showcase a diverse selection of Montana sapphire engagement rings, each telling a story of natural beauty and craftsmanship. But our journey with Montana sapphires doesn’t end there! Read our next blog post for an exclusive tour of our loose Montana sapphires—ideal for creating custom rings or other jewelry.

About the Author
Sarah O. Editorial Team
We’re the storytellers behind Sarah O. Jewelry, sharing the latest trends, timeless designs, and insider tips. From gemstones to craftsmanship, we're here to help you discover jewelry that speaks to your story.
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