image credit The most expensive materials on earth tend to be valuable because of their rareness. Notwithstanding, a few materials have an inflated value because they are traded on black markets. Right now, the list of the most costly materials on earth are dominated by rare earth substances i.e. platinum, valuable pearls, precious stones, illegal drugs and propelled materials that are perilous and difficult to produce. These substances share a consistent theme of being high in demand and low in supply. 20. Saffron : image credit Saffron is a kind of flower-plant. It has fantastic taste and great health benefits. It can be used in natural remedies for everything from depression to menstrual cycles. Saffron is too costly because its production process is highly time and effort consuming. About one hundred & fifty saffron flowers are needed to produce one gram of processed saffron. Price Per Gram : $11 19. White Truffles : image credit White Truffle is ...