Natural blue cobalt spinel, 2.13 carats, cushion cut, untreated, vivid cobalt blue color, Tanzania origin, GFCO certified gemstone

Natural Blue Cobalt Spinel 2.13 ct – Cushion Cut, Untreated, GFCO Certified

Name: Natural Blue Cobalt Spinel 2.13 ct – Cushion Cut, Untreated, GFCO Certified
Brand: SOSNA Gems & Jewellery
SKU: 2991465
Price: 32512.00 CZK
Availability: InStock

32.512,00 CZK

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Gemstone Specification

Carat Weight 2.13

Dimensions 7.92 × 6.22 × 5.39 mm

Color Colbalt Blue

Clarity Eye Clean

Shape Cushion

Treatment No Treatment

Origin Tanzania

Certification GFCO

This natural blue cobalt spinel weighs 2.13 carats and displays a vivid blue color with exceptional saturation and attractive brilliance. The gemstone is expertly fashioned in a cushion cut measuring 7.92 × 6.22 × 5.39 mm, creating elegant proportions and lively light reflection that enhance its rich cobalt-blue appearance. Cobalt spinel is among the rarest and most desirable spinel varieties, highly valued for its intense electric-blue coloration and collector appeal.

Originating from Tanzania, this gemstone remains completely untreated, with no heat treatment or enhancement, preserving its authentic natural beauty and rarity. The combination of brilliant crown faceting and step-cut pavilion provides outstanding brilliance and depth while maintaining the gemstone’s refined cushion shape. Certified by GFCO Gem Lab Switzerland, this spinel comes with independent verification of its natural origin and untreated status.

Its rare cobalt-blue coloration, untreated nature, and Swiss laboratory certification make this spinel an exceptional choice for collectors and bespoke high-end jewelry creations.

Natural Blue Cobalt Spinel 2.13 ct – Cushion Cut, Untreated, GFCO Certified

32.512,00 CZK

From gemstone to jewelry

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Gemological overview

Technical and gemological information about this gemstone variety.

Gemological profile

Spinel is a natural magnesium aluminum oxide mineral valued for its excellent transparency, vibrant color range, and clean crystal structure. In gem-quality material, spinel is appreciated for its clarity and lively appearance, with colors ranging from red, pink, and purple to blue, gray, and black, depending on trace elements present during formation.
Chemically composed of magnesium aluminum oxide (MgAl₂O₄), spinel crystallizes in the cubic crystal system and belongs to the oxide mineral group. In transparent gem-quality specimens, it typically displays a vitreous luster with high clarity.
The refractive index of spinel generally ranges from approximately 1.718 to 1.738, producing a bright, balanced brilliance without excessive dispersion. Spinel is found in several regions worldwide, with notable sources including Myanmar, Sri Lanka, Vietnam, Tanzania, and parts of Afghanistan, each associated with slightly different color characteristics.

Durability & suitability

With a hardness of 8 on the Mohs scale, spinel offers very good durability suitable for everyday jewelry when properly set and worn with standard care. Its lack of cleavage contributes to excellent resistance against impact and abrasion compared to many other colored gemstones.
Spinel performs reliably in rings, pendants, earrings, and bracelets, including designs intended for frequent wear. Its combination of durability, stable color, and refined brilliance makes spinel a practical and versatile choice for both everyday jewelry and elegant, statement-oriented designs.

Treatments & authenticity

Spinel is most commonly found in nature without the need for enhancement. Treatments are generally uncommon, and gem-quality spinel is typically valued for its natural color and clarity.
Any treatments or enhancements, if present, are always clearly stated for each individual gemstone. Every stone is professionally examined, and transparent disclosure is regarded as a fundamental part of responsible gemological practice, allowing clients to make informed and confident decisions.

Our approach to gemstones

We focus primarily on natural, untreated gemstones, valued for their authenticity and inherent beauty.
Any treatments or enhancements are always clearly disclosed, allowing our clients to make informed decisions based on transparent gemological standards.

Sosna Gems is not a licensed financial advisor. Gemstones are collectibles, not securities. Past performance is not indicative of future results. Legal & risk disclosure .