1.76 Carat Natural Cobalt Blue Spinel – Tanzania
1.76 Carat Natural Cobalt Blue Spinel – Tanzania
An impressive 1.76 carat natural cobalt spinel from Tanzania, featuring a rich, sophisticated blue color and a striking octagonal step cut.
The broad step facets give this gemstone a bold architectural appearance, producing flashes of blue across the stone as lighting and viewing angle change. Its deep navy-to-steel-blue character makes it an excellent choice for a collector seeking something considerably less common than traditional blue sapphire.
The accompanying gemological report identifies the gemstone specifically as NATURAL COBALT SPINEL, with Tanzanian origin and no indication of heat treatment.
Gemstone Details
- Gemstone: Natural Cobalt Spinel
- Weight: 1.76 carats
- Color: Blue
- Origin: Tanzania
- Shape/Cut: Octagon Cut
- Measurements: 6.68 × 6.30 × 4.6 mm
- Treatment: No indication of heat
- Hardness: 8 on the Mohs scale
- Condition: Loose gemstone
- Gemological Report: AIG – American International GemLab
- Report No.: GEM20260831178597
The Rarity of Cobalt Spinel
Blue spinel is among the more unusual members of the spinel family. Cobalt-bearing examples have developed a particularly strong following among collectors because cobalt can contribute to the blue coloration found in certain exceptional natural spinels.
Unlike many colored gemstones encountered in the marketplace, the accompanying report for this specimen states no indication of heat.
At 8 on the Mohs scale, spinel also offers excellent durability for fine jewelry. This stone could remain as part of a loose-gem collection or become the centerpiece of a custom-designed ring or pendant.
Collector Gemstone — $3,500
The combination of cobalt spinel identification, Tanzanian origin, 1.76-carat size, natural unheated status, and distinctive octagonal cut makes this a compelling specimen for the serious colored-gemstone collector.
The exact gemstone pictured is the gemstone you will receive.
Macro photography and specialized lighting are used to show the gemstone’s details. Natural inclusions, reflections, and variations in color may appear more prominent under magnification than during normal viewing.