SPINEL
The Crown Gem Mistaken for Ruby
Spinel is a fascinating gemstone known for its vivid colors, natural brilliance, and remarkable history. For centuries, red spinels were mistaken for rubies, including the famous Black Prince’s Ruby set in the British Imperial State Crown.
1. What Is Spinel
Spinel is a hard, glassy gemstone that forms naturally as sharp, octahedral crystals. It is a mineral made primarily of magnesium and aluminum oxides, which give it excellent durability and clarity. Because of its crystal structure, spinel often appears with well-defined, pointed shapes. This gemstone, which shares its name with the mineral, has long been valued for both its strength and beauty. Its hardness makes it suitable for everyday jewelry.
2. Spinel Colors
Spinel occurs in a wide range of colors, including red, pink, blue, orange, purple, and black. The most valuable shades are bright red, cobalt blue, vivid pink, and orange. Red and pink spinels owe their color to the presence of chromium. Blue spinels can be colored by iron, while the most vibrant blue tones come from cobalt. Purple and orange varieties are created by a combination of iron and chromium.
3. The Origin of the Name
The name “spinel” is believed to come from the Latin word spina, meaning “spine” or “thorn.” This name likely refers to the sharp, pointed crystal shapes in which spinel is often found. These naturally sharp edges helped distinguish spinel visually, even before its true identity was understood. Despite this, its resemblance to other gemstones caused centuries of confusion. Its striking appearance contributed greatly to its long-standing fame.
4. Spinel Mistaken Identity
For more than a thousand years, spinel was commonly mistaken for ruby or sapphire. In 1783, mineralogist Jean-Baptiste Louis Romé de Lisle officially identified spinel as a separate mineral. Many famous “rubies” in history later turned out to be spinels. One of the most famous examples is the Black Prince’s Ruby in the British Imperial Crown, which is actually a red spinel. This discovery reshaped gemstone history.
5. Spinel Mining Locations
Spinel is mined in several parts of the world, including Sri Lanka, Vietnam, Myanmar, Thailand, and Cambodia. Important sources are also found in Afghanistan, Tajikistan, Nepal, Madagascar, Nigeria, Tanzania, and Australia.
6. The Samarian Spinel
The Samarian Spinel is one of the most famous spinels ever discovered, weighing an impressive 500 carats. It is part of the Iranian Crown Jewels and is renowned for its exceptional size and historical significance.
7. Spinel Hardness
Spinel ranks 8 on the Mohs scale of hardness, making it a durable and long-lasting gemstone. Its good resistance to scratching makes it suitable for many types of jewelry. This level of hardness allows spinel to maintain its polished appearance with proper care.
8. August Birthstone
Spinel is an official birthstone for August. It is also traditionally associated with energy renewal, resilience, and rejuvenation. Its wide range of colors gives August-born individuals many beautiful options to choose from.
9. How to Clean Spinel
10. Refractive index
Spinel has a refractive index of approximately 1.718 to 1.730. This measures how strongly light bends as it passes through the gemstone. Its refractive index contributes to spinel’s bright appearance and natural brilliance.
📌 Spinel: Summary
- Hard, durable gemstone; forms sharp octahedral crystals
- Colors: red, pink, blue, orange, purple, black;
red/pink from chromium, blue from cobalt/iron - Often mistaken for ruby; like famous:
Black Prince’s “Ruby” in British Crown is actually spinel - Found in Myanmar, Sri Lanka, Vietnam, Thailand,
Madagascar, Africa - Hardness 8 on Mohs scale; August birthstone
- Spinel has a refractive index of approximately 1.718 to 1.730
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