Tiger's Eye Tumbled Stone

Tiger eye is quartz - SiO₂, Mohs 6.5–7 - with a structure unlike any other quartz in this range. It began as crocidolite, a fibrous blue mineral; over geological time silica replaced the fibres while keeping their alignment. The parallel fibres are what catch the light.

The moving band is chatoyancy - from the French for cat’s eye - an optical effect of that fibrous structure. Light reflects along the fibres, so a bright line travels across the stone as it turns. The gold-brown colour comes from iron oxides left behind by the original mineral.

The classic deposits lie in the Northern Cape of South Africa, where most of the world’s tiger eye has been mined since the nineteenth century.

Asked often

Is the colour natural?
The golden-brown is natural. Red tiger eye on the market is usually heat-treated, and the blue sold as hawk’s eye is the original fibre before quartz replaced it - this is the untreated gold.

Does it contain asbestos?
The original fibre was an asbestos mineral, but in tiger eye it has been replaced and sealed by quartz. Polished stones are stable and safe to handle.

Why does the band of light move?
Light reflects along the parallel fibres inside the stone, so the band travels as the angle changes. Turn it in the hand and it answers.

How do I look after them?
Wipe with a soft, slightly damp cloth and dry. At Mohs 6.5–7 they wear well and need little care.

1. Carried in a pocket or a bag, or held in the hand.
2. Kept in a small dish, on a desk, or on a shelf - each stone is a little different.
3. Wipe with a soft, slightly damp cloth and dry; hard-wearing at Mohs 6.5–7.

Each stone is tumble-polished and unique, so a set varies a little stone to stone. Many keep a stone where they will see it each day, or carry one in a pocket; that is a matter of preference.

Pocket stones to keep and carry. Wipe with a soft cloth; hard-wearing at Mohs 6.5–7. Keep them together in a pouch so harder edges do not scratch softer stones.

• Stone: Tiger's Eye · golden-brown quartz
• Hardness: Mohs 6.5–7
• Character: Chatoyant · banded gold to brown
• Treatment: None · untreated
• Form: Tumbled stones · polished, each unique · sold in a set
• Origin: South Africa
• Care: Wipe with a soft cloth

When the first pieces reached Europe in the nineteenth century, tiger eye was priced as a rare gem; the scale of the Northern Cape deposits later made it an everyday stone. The supply changed, not the stone - the same band of light, at the price of a palm stone.

Across many cultures, stones carrying a moving eye of light were worn as watchful tokens - named here as what people believed. What the eye watches for is, as ever, the holder’s to decide.