How the value of rocks has rocketed...

WHITE DIAMOND £14,700*

Has risen by just 3.5 per cent over the past decade – considerably less than those with colourful hues. Even so, they are still the most valuable.

RUBY £6,700*

This red stone can contain hues of pink, orange or purple. A favourite of the Victorians and believed to bring luck. Now a symbol of love. Burmese rubies in particular have risen in value by 1,100 per cent in ten years.

SAPPHIRE £6,250*

Examples from Kashmir have risen in value by as much as 900 per cent over a decade. Usually blue, sapphires also come in pink, yellow, and a pinkorange. The ancient Greeks believed they protected owners from harm and envy.

EMERALD £5,950*

Rarer than diamonds. Emeralds from Colombia have risen in value by 2,000 per cent in a decade. Ancient Egyptians believed they symbolised eternal youth.

* price of a one carat, high quality stone