Material properties of diamond Material properties of diamond Diamond is the allotrope of carbon in which the carbon atoms are arranged in the specific type of cubic lattice called diamond cubic. Diamond is an optically isotropic crystal that is transparent to opaque. Diamond is the hardest naturally occurring material known. Yet, due to important structural weaknesses, diamond's toughness is only fair to good. The precise tensile strength of diamond is unknown, however strength up to 60 GPa has been observed, and it could be as high as 90–225 GPa depending on the crystal orientation. The anisotropy of diamond hardness is carefully considered during diamond
Hope Diamond long been rumored to carry a curse, possibly due to agents trying to arouse interest in the stone. It was last reported to be insured for $250 million. The Hope Diamond, also known as Le Bijou du Roi ("the King's Jewel"), Le bleu de France ("France's Blue"), and the Tavernier Blue, is a large, , deep-blue diamond, and now housed in the National Gem and Mineral collection at the National Museum of Natural History in Washington, D.C. It is blue to the naked eye because of trace amounts of boron within its crystal structure, and exhibits a red phosphorescence under