Spinel is a magnesium aluminum oxide mineral with the chemical formula MgAl2O4. It is highly valued in the gem world for its vibrant colors, excellent durability, and rarity. Spinel has often been mistaken for other gemstones, particularly rubies, due to its vivid hues and historical significance.

Key Characteristics:

1. Color: Spinel occurs in a wide range of colors, including:

• Red (most prized, often mistaken for ruby)

• Pink

• Orange

• Blue (highly sought after, especially cobalt blue)

• Purple

• Lavender

• Black and Gray

Its color depends on trace elements like iron, chromium, and cobalt.

2. Luster: Spinel has a vitreous luster, giving it a glassy and attractive appearance.

3. Hardness: With a Mohs hardness of 7.5 to 8, spinel is durable enough for all types of jewelry.

4. Transparency: It ranges from transparent to opaque, with the finest specimens being highly transparent.

5. Crystal System: Spinel crystallizes in the isometric (cubic) system, often forming octahedral crystals.

6. Birefringence: Spinel is singly refractive, unlike many gemstones, which adds to its clarity and brilliance.

7. Origin and Occurrence: Spinel is commonly found in metamorphic and alluvial deposits, often alongside corundum (ruby and sapphire). Major sources include:

• Myanmar (Burma)

• Sri Lanka

• Tanzania

• Vietnam

• Madagascar

Uses:

• Jewelry: Spinel is highly prized for rings, necklaces, and other fine jewelry due to its hardness and vivid colors.

• Historical Significance: Many famous “rubies,” such as the Black Prince’s Ruby in the British Crown Jewels, are actually spinels.

Unique Features:

• No Heat Treatment: Unlike many gemstones, high-quality spinel is typically untreated, making its natural beauty even more desirable.

• Distinctive Glow: Some spinels, especially reds and pinks, exhibit a “glow” due to their fluorescent properties.

Spinel’s vibrant colors, rarity, and durability have earned it a growing reputation as a gemstone in its own right, rather than merely a substitute for ruby or sapphire.