According to Obito Uchiha, the sword is a holy relic which Hagoromo had used to shape the world, and the blade was powerful enough to just as easily destroy it by his own hands. While being wielded by Obito, this sword was partially destroyed by Sasuke Uchiha's Susanoo Sword while enhanced by senjutsu and Kurama's chakra.
The double-helix shape of the sword is most likely a reference to DNA, a molecule existing in all known living organisms.
The sword's name, as well as the legend of it being the tool used by Hagoromo Ōtsutsuki to "shape the world", is likely a reference to the Amenonuhoko (天沼矛, Literally meaning: Heavenly Jewelled Spear). In legend, Amenonuhoko was the spear used to shape the primordial land from the sea. It was later used by Izanami and Izanagi to create the first island, on which they then dwelt.