Cobalt Blue Spinel
Cobalt blue spinel is one of the rarest and most valuable varieties of the spinel gemstone. Known for its vivid electric blue color, cobalt spinel is highly prized by collectors, gemstone investors, and fine jewelry designers.
The remarkable blue color is caused by trace amounts of cobalt within the crystal structure. Because cobalt rarely occurs during spinel formation, natural cobalt blue spinels are extremely scarce and highly sought after.
Origin of Cobalt Blue Spinel
Cobalt blue spinel has been discovered in only a few locations worldwide. Important sources include Vietnam, Tanzania, and Myanmar. Among these sources, the Luc Yen region of Vietnam is especially famous for producing intensely colored cobalt spinels.
These gemstones are typically found in marble-hosted deposits similar to those that produce ruby and other spinel varieties.
Color and Characteristics
The defining feature of cobalt spinel is its striking blue color. Unlike many blue gemstones that may appear dark or inky, cobalt blue spinel often displays a bright and vibrant electric blue tone.
- Color: vivid cobalt blue
- Hardness: 8 on the Mohs scale
- Clarity: often eye-clean
- Treatment: usually untreated
Because of its exceptional color and rarity, cobalt blue spinel is considered one of the most desirable collector gemstones.
Cobalt Blue Spinel vs Blue Sapphire
Cobalt blue spinel is sometimes compared to blue sapphire because both gemstones display attractive blue colors. However, they differ in composition and rarity.
- Spinel hardness: 8 Mohs
- Sapphire hardness: 9 Mohs
- Spinel is often untreated
- Sapphire is commonly heat treated
While sapphire is generally more widely known, fine cobalt blue spinel is often rarer and highly valued among collectors.
Rarity and Value
Cobalt blue spinel is extremely rare in nature. Stones with strong color saturation and good clarity can command high prices in the gemstone market.
Larger stones above 2 to 3 carats are especially uncommon and are often sought after by gemstone collectors and investors.
Explore Natural Spinel Gemstones
If you are interested in rare collector gemstones, explore our selection of natural spinel gemstones available in a variety of colors and sizes.