Red Spinel vs Ruby: The Connoisseur's Comparison

For most of history, the two were the same stone. The "Black Prince's Ruby" in the British Imperial State Crown and the "Timur Ruby" are both, in fact, spinels — celebrated as rubies for centuries until gemology could tell them apart. That story is the perfect introduction, because red spinel is not a ruby imitation; it is a distinct, fine gem that the trade's most discerning buyers increasingly seek in its own right.

In one line: ruby is the storied red with the famous name and the top-tier market; red spinel is the brilliant, usually untreated red — often a connoisseur's choice for natural colour and value.

At a glance

The key difference: spinel is usually untreated

Here is what wins spinel its devotees. Most fine ruby on the market is heat-treated to refine colour and clarity — an accepted, disclosed practice, and no flaw. Most fine red spinel, by contrast, is simply untreated: the colour you see is the colour the earth made, no heat required. For a buyer who values "natural, just as it came," a fine untreated spinel offers that without the premium an untreated ruby commands. It is one of the last fine reds you can routinely buy untreated.

"I want to set the record straight about red spinel... people often believe, and were often told, that red spinel was believed to be ruby." — David Saad, Skyjems

Colour and brilliance

Spinel's reds run from a pure, ruby-like red through raspberry and hot pink to the electric, slightly orange-red of the celebrated Mahenge (Tanzania) material. It is singly refractive and beautifully bright. Ruby's benchmark is a saturated, slightly purplish-to-pure red — the colour that has defined "precious" for millennia. At their best, a fine red spinel and a fine ruby can look strikingly similar; the difference the eye misses is exactly the one history missed.

Value and standing

Ruby holds the higher ceiling and the legendary name — for the top tier of red, nothing displaces it, and fine ruby remains a blue-chip stone. Spinel sits a step below on name and price, which is its opportunity: comparable brilliance and a usually-untreated, natural red, frequently at meaningfully better value. As more buyers learn the story, fine spinel's standing — and prices — have been climbing.

So which should you choose?

• Ruby for the classic name, the top-tier market, and the deepest collecting pedigree.
• Red spinel for a brilliant, usually untreated natural red at strong value — the knowing buyer's choice, and a wonderful stone in its own right.

We carry both — fine ruby and natural red spinel — with treatment disclosed on every stone. Inquire with the Curator to compare them side by side, or browse the spinel and ruby collections. Toronto: 416-366-3335.

Frequently asked questions

Is spinel a good alternative to ruby? Yes — and increasingly regarded as a fine gem in its own right, not merely a substitute. Red spinel offers brilliant, usually untreated natural colour and excellent durability (Mohs ~8), often at better value than ruby. Ruby keeps the classic name and the higher market ceiling.

Is red spinel treated? Usually not. Most fine red spinel is untreated — the colour is natural — which is a major part of its appeal. Most ruby, by contrast, is heat-treated (a standard, disclosed practice).

What's the difference between spinel and ruby? They are different minerals: spinel is magnesium aluminate; ruby is corundum. Spinel is singly refractive and usually untreated; ruby is doubly refractive and usually heated. Historically the two were confused — several famous "rubies" are actually spinels.

Is spinel durable enough for a ring? Yes. At about 8 on the Mohs scale, spinel is well suited to rings and everyday wear, just below ruby's 9.

Is red spinel a good investment? Fine, untreated red spinel — especially vivid Mahenge material — has seen rising demand and prices as buyers discover it. Ruby remains the higher-ceiling classic. Both are gems to enjoy first; rarity, colour and documentation hold value.