Featured News. Greens Sand has been in the silica sand industry since 1979 and has been a distributor of specialised silica sand to the Industrial as well as Leisure market for over 30 years, distributing nationally and across borders. We store a wide range of grades of silica sands.
Standing almost due east of the Reflecting Pool and the Lincoln Memorial, the monument, made of marble, granite, and bluestone gneiss, is both the world's tallest stone structure and the world's tallest obelisk, standing 555 feet 7 11â32 inches (169.351 m) tall.t the time of its completion, it was the tallest building in the world, a title it retained until the Eiffel Tower was completed in 1889; however, the Washington Monument is still the tallest stone structure in the world.
The base of the obelisk at the Washington monument is 55 feet 1Â½ inches (16.8 m). It tapers to the capstone, which has a base of 3 ft x 3 ft (0.91 m). The aluminum apex has aâ¦ square base of 5.6 inches (14 cm). The official height is 555 feet, 5â inches (169.294 m).