Quartz Sphere, by Unknown, c. 1930s, Smithsonian Archives - History Div, The world's largest, flawless quartz sphere is 242,323 carats, weighs 106.75 lbs. (48.5 kg), and measures 12.9 inches (32.7 cm) in diameter, from the collections of the United States National Museum, now the National Museum of Natural History. The sphere was cut and polished in China in 1923-1924, and the crystal from which it was cut may have come from Burma. The sphere was a gift of Mrs. Worcester Reed Warner in 1930..