Red Spinel vs Ruby: How to Tell These Rare Gemstones Apart

For centuries, fine red spinels were mistaken for rubies because the two gemstones can share an intense, glowing red colour. Some celebrated stones in historic royal collections were later identified as spinel rather than ruby. Today, gemmological testing separates them clearly, but the comparison remains useful for collectors and jewellery designers because both can offer exceptional beauty, rarity and character.

Deep red gemstones showing why fine spinel and ruby were historically confused

Different Minerals, Similar Colour

Ruby is the red variety of corundum, while spinel belongs to a separate mineral group with its own crystal structure. Chromium is responsible for much of the red colour in both stones, which explains their visual similarity. Ruby is generally harder, but spinel is still durable enough for many forms of fine jewellery when it is carefully set and worn with appropriate care.

A polished red gemstone whose colour alone cannot confirm whether it is ruby or spinel

Rarity and Treatment Can Affect Value Differently

Fine rubies have a long-established market and exceptional untreated examples can command very high prices. Red spinel has historically been less recognised, but strong natural colour, clarity and scarcity have brought it increasing attention. Another distinction is treatment: ruby is commonly heat treated, whereas spinel is more often found without enhancement, although every important stone should still be assessed individually and supported by appropriate documentation.

A group of rare red gemstones, where origin, treatment and natural quality shape collectability

Certification Is the Only Reliable Answer

Colour, inclusions and brilliance can provide clues, but appearance alone is not enough to identify a valuable red gemstone with confidence. A gemmological laboratory can distinguish spinel from ruby and report detectable treatments. For buyers considering an important stone, certification protects against misidentification and ensures that price is based on accurate information rather than assumption.

Find Your Perfect Ruby Today

Rare gemstones selected through specialist sourcing and supported by accurate identification

To source a certificated ruby, red spinel or another rare coloured gemstone, contact SICO International and speak with our London team about your collection or jewellery project.