For the first time in its 13-year history, the jewelry house De Beers—best known for its engagement rings and wedding bands—has introduced ceramic as a structural material in its designs. (The De Beers jewelry company was established in 2001; the De Beers mining company is more than 120 years old.) The two rings ($4,800 apiece) are available in white or black ceramic (called Daylight Lotus and Moonlight Lotus, respectively) and are set with white diamonds. Their design draws inspiration from the company’s…