Deep beneath Earth’s surface, the mystery element transforms into dazzling diamonds. At temperatures averaging 1,100°C (2,000°F) and under intense pressure of about 54,000 kilograms per square centimeter (770,000 pounds per square inch), the element’s atoms are squeezed together into gemstones. Diamonds’ tightly packed atoms make them the hardest known natural material on Earth. That’s why along with adorning jewelry, diamonds are used to drill, cut, and grind other tough substances. Game over already? Score 100 points. If not, read clue 2.