|Spinel is a special gemstone in many ways. For centuries it was mistaken for ruby and gained undeserved fame. Today fine red spinel is more rare than ruby but less valuable. That looks like a delayed revenge for its questionable past.
Its name derivation is also ambiguous. Experts are undecided whether it derives from the Greek word for "spark" or the Latin "thorn".
Although commonly thought of as red, spinel can be found in a range of beautiful pastel shades. These outstanding shades of pink, purple, orange, blue, plus every combination in between make spinels some of the most desirable stones in the world.
Due to its excellent hardness (8 on Mohs scale) and high clarity spinel is a very fine gem for jewelry of all kinds. Spinel is never treated in any way and continues to be a great substitute for ruby and sapphire as well.
Where is Spinel found?
Common Spinel Treatments
Spinel legends & lore
Although commonly thought of as red, spinel can be found in a range of beautiful pastel shades. These outstanding shades of pink, purple, orange, blue, plus every combination in between make spinels some of the most desirable stones in the world. Of particular interest is a vivid hot pink with a tinge of orange that is mined in Burma that is one of the most spectacular gemstone colors in any gem species. Spinel also comes in beautiful blues, which are sometimes called cobalt spinel, but these are rare.
The coloring agents in spinel are iron, chromium, vanadium and cobalt. Within the spinel group some trade names have become common:
Flame spinel: Bright orange to orange-red spinel
Balas spinel: Pale red spinel
Pleonaste: Dark green to blackish, opaque spinel
Hercynite: Dark green to black spinel
Grahnite: Blue, violet, or dark green to blackish spinel
Gahnospinel: Blue to dark blue or green spinel
Picotite: Brownish, dark green, or blackish spinel
Large stones are rare and star spinels are very rare.
The most outstanding color is ruby-like red or sapphire-like blue.
Under UV-light red spinel intensifies its red color strongly. Blue spinel weakens and turns reddish, green.
Fine spinel are transparent and most sought after. Opaque spinel, cut en cabochon, can sometimes display a star effect, a valuable rarity.
A brilliant cut serves a very clear spinel best. Due to its hardness spinel is perfect for all jewelry uses. It is most often faceted in oval, round, or cushion shapes.
Spinel location and deposits
Spinel occurs with ruby and sapphire mainly in important deposits found in Cambodia, Myanmar, Sri Lanka and Thailand. Other locations are in Afghanistan, Australia, Brazil, Madagascar, Nepal, Nigeria, Tadzhikistan, Tanzania and the United States.
Common Spinel treatments
Spinel is never treated in any way.
Some famous large rubies, such as the "Black Prince's Ruby" and the "Timur Ruby" in the British Crown Jewels are actually spinels, because until the beginning of the 19th century spinels were thought to be rubies.
The two largest spinels, each 520 ct, are on display at the British Museum of London. The "Diamond Fund" in Moscow owns a spinel of 400 ct.
Color: Red, orange, yellow, brown, blue violet, purple, green, black
Chemical composition: MgAl2O4 magnesium aluminum oxide
Crystal system: (Cubic) octahedron, twins, rhombic dodecahedron
Hardness: 8 (Mohs scale)
Specific gravity: 3.54 - 3.63
Refractive index: 1.712 - 1.762
Color of streak: White,
Absorption spectrum: Red spinel: 685, 684, 675, 665, 656, 650, 642, 632, 595-490, 465, 455
Fluorescence: Red spinel strong, red; Blue spinel weak, reddish, green
The Spinel zodiac, myth & legend
Spinel has been most famous when mistaken for ruby or sapphire. Only recently has it gained respect in its own right.