of corundum, spinel has a different crystal structure and optical properties. Key Characteristics of Red Spinel • Color: Deep red to pinkish-red, sometimes with orange or purplish undertones. • Hardness: 7.5 – 8 on the Mohs scale (durable but slightly softer than ruby). • Luster: Vitreous (glassy) and highly reflective. • Clarity: Usually eye-clean, meaning it has minimal visible inclusions. • Refractive Index: 1.71 – 1.76, giving it excellent brilliance. • Formation: Found in metamorphic and alluvial deposits, often alongside rubies and sapphires. • Sources: Myanmar (Burma), Sri Lanka, Vietnam, Tanzania, and Afghanistan are known for high-quality red spinel. Historical Significance For centuries, red spinel was mistaken for ruby and treasured by royalty. Some of the world’s most famous “rubies,” such as the Black Prince’s Ruby and the Timur Ruby in the British Crown Jewels, are actually red spinel. Uses and Value • Prized in fine jewelry for its brilliance and rarity. • More affordable than ruby, yet just as visually stunning. • Rarely treated or enhanced, making natural specimens highly desirable. Would you like a comparison between red spinel and ruby?