Manganese nodules, also known as nodules, manganese ball, manganese group, manganese and other tumors, it is an iron and manganese oxides aggregates, often black and brown color black. Combination of various forms of manganese, a spherical, oval-shaped, potato-shaped, grape-like, flat, slag-like and so on. Size changes the size of manganese nodules is relatively poor, from a few microns to tens of centimeters have, the greatest weight of dozens of kilograms.

     Individual nodules are very small, the difference is very poor. As small as grains of sand, less than 1 mm in diameter, or smaller, should be observed under the microscope; large up to tens of centimeters in diameter; the most common is 0.5 cm.  

  According to historical records, the Soviet research ship "Warrior" at the 43rd sailing in the Hawaiian Islands at the western slopes of the underwater mountain range, at 3,800 meters under the sea in the discovery of a block weighing 2,000 kilograms of manganese nodules has been known manganese nodules for the world's largest block, I am now a few nodules in the collection, there is a weight of 3,000 kg, then it is still the world's largest manganese nodules block.