Seven-figure diamonds and the stars who wear them.Credit: Getty Images / InStyleThe GistOver the years, red carpets have played host to jewelry worth trillions of dollars.Some of the most expensive jewelry ever worn only became so after its wearer’s death.Modern celebrities, like Beyoncé and Gigi Hadid, have also worn their fair share of extravagant jewels.Though more women billionaires exist now than ever before (Rihanna, Taylor Swift, Selena G…