Top 16 Most Expensive Materials in the World The most expensive substance of the planet, based on the price per gram, arranged with an increase in value. 16. Saffron - $ 11/gramm Saffron is a flowering plant that can be used as a natural remedy virtually all ailments ranging from depression and ending with menstrual cycles. The dried stigmas of the saffron flower seeds are used as a spice and food color orange. Perhaps there are properties allow to slow vision loss in older people. 15. Gold - $ 56/gramm In addition to the traditional use in jewelry, gold can be used as an electrical conductor and to prevent corrosion. Gold - a very heavy metal: the density of pure gold equal to 19 621 kg / cubic meter (ball of pure gold, 46 mm in diameter has a mass of 1 kg). The high density of gold makes it easier to catch. 14. Rhodium - $ 58/gramm Rhodium is mainly used in catalytic converters to reduce carbon emissions from cars. No biological role in human life, this highly toxic me...