Spinel Gemstone Description

Spinel is a rare and valuable gemstone known for its exceptional brilliance, durability, and wide range of colors. It is composed of magnesium aluminum oxide (MgAlâ‚‚Oâ‚„) and forms in octahedral crystals. Historically, spinel was often mistaken for ruby or sapphire, and some of the worldâ€TMs most famous “rubies†in royal collections are actually spinels.

Key Characteristics of Spinel

• Color:

• Found in red, pink, orange, blue, violet, purple, and black.

• Red spinel closely resembles ruby and is the most valuable.

• Blue spinel (especially cobalt spinel) can be as striking as sapphire.

• Hardness: 7.5 – 8 on the Mohs scale (durable but slightly softer than ruby and sapphire).

• Luster: Vitreous (glassy) and highly reflective.

• Clarity: Usually eye-clean, meaning it has minimal visible inclusions.

• Refractive Index: 1.71 – 1.76, giving it exceptional brilliance.

• Formation: Found in metamorphic and alluvial deposits, often alongside corundum (ruby and sapphire).

• Sources:

• Myanmar (Burma) – Produces some of the finest red spinels.

• Sri Lanka – Known for various spinel colors.

• Tanzania, Vietnam, Afghanistan, and Madagascar – Other key sources.

Historical Significance

Many famous “rubies†in history are actually red spinels, including:

• The Black Princeâ€TMs Ruby – A large red spinel set in the British Imperial State Crown.

• The Timur Ruby – A treasured spinel once owned by Mughal emperors.

Spinel vs. Other Gemstones

• Spinel vs. Ruby – Both can be deep red, but spinel lacks rubyâ€TMs strong fluorescence