Increased demand for coloured stones has seen their prices soar . production of diamonds has been vastly overtaken by sapphires and rubies . Auctioneers are now making them a better investment than diamonds . Celebrities such as Kate diamonds have revived the craze .
Increased demand for coloured stones has seen their prices soar . Value of diamonds has been vastly overtaken by sapphires and rubies . Auctioneers are now branding them a better investment than diamonds . Celebrities such as Kate Middleton have driven the craze .