Spinel Buying Guide: The Great Impostor

Spinel spent centuries as history's most successful gemstone impostor, and understanding why is the fastest way to understand what makes it worth buying today.

Mistaken for ruby, for centuries

Before modern chemistry could distinguish gemstones by composition rather than colour, red spinel was repeatedly identified as ruby — including some of the most famous "rubies" in existence. The 170-carat stone mounted at the front of the British Imperial State Crown, celebrated for five centuries as the Black Prince's Ruby, is a spinel. So is the 352-carat Timur Ruby and the large red stone in the Russian imperial crown. When a large, exceptionally clean red gem survives from antiquity, it's now understood to almost always be spinel — a ruby of that size and clarity at that age essentially doesn't exist in nature.

Why spinel achieves that clarity where ruby often can't

Spinel crystallises with naturally exceptional clarity far more consistently than ruby does, which is a large part of why historical "rubies" of impossible-seeming size and cleanliness kept turning out to be spinel once testing became possible. It's also, unlike the vast majority of ruby and sapphire on the market, typically untreated — no standard heat treatment applied, sold and priced as natural colour as found.

Colour range and value

Red and pink are the most commercially important spinel colours, but it also occurs in blue, violet, orange and grey tones. Demand has picked up meaningfully in recent years as more buyers learn the history, but general awareness is still low relative to corundum (ruby and sapphire), which keeps prices well below equivalent-quality ruby or sapphire for now — a real opportunity for buyers who want genuine rarity and history without corundum pricing.

What to check before buying

• Confirm species on an independent report — spinel and ruby can look similar enough that lab confirmation matters, especially at higher values.
• Treatment status — most spinel is untreated, which should be stated explicitly; any treatment should be disclosed and priced accordingly.
• Origin, where determinable — Burma (Myanmar) and Sri Lanka are the classic sources, alongside more recently significant Tanzanian material.

Related reading

• Ruby buying guide: pigeon blood, origin & treatment
• Birthstones by month: the complete guide
• Gemstone treatments explained

Sources: spinel history and the Black Prince's Ruby identification per GIA (gia.edu) and jewellery-history reporting (M.S. Rau, Sosna Gems).