Ironsand, also known as iron-sand or iron sand, is a type of sand with heavy concentrations of iron. It is typically dark grey or blackish in colour. It is composed mainly of magnetite, Fe3O4, and also contains small amounts of titanium, silica, manganese, calcium and vanadium. Ironsand has a tendency to heat up in direct sunlight, causing temperatures high enough to cause minor burns. As such it forms a hazard in New Zealand at popular west-coast surf beaches such as Piha. Occurrence Ironsand is found worldwide. Although the iron mineral composition of the ironsand is mostly magnetite, the sand is usually mixed with other types of sand that washes downriver or ashore from mountainous or underwater deposits. The exact composition of the sand mixture may vary drastically even in the same geographic region. In some areas the sand may contain mostly quartz, while in others the sand may be made primarily from volcanic rock such as basalt, depending on the types of minerals along the water's path. The ironsand is typically picked up along the way from beds, veins, or inclusions of magnetite, which may originate a great distance from the sand deposits, and washed downstream or along the currents with the rest of the sand. Being heavier than the other sands, it is often deposited in areas where the water experiences a sudden change in direction or speed, such as the widening of a river or where the waves ebb and flow against the shoreline. The ironsand is mixed with the other sands as small grains of black or dark-blue magnetite. Sand used for mining typically had anywhere from 19% magnetite to as low as 2%. The ironsand typically had to be separated from the sand mixture. Because the magnetite is usually heavier than quartz, feldspar, or other minerals, separation was usually done by washing it in sluice boxes (a method similar to gold panning but on a larger scale). Sluice separation typically yielded concentrations of magnetite ranging from 30 to 50%, depending on the type of sand and the method used. In the early 20th century a process of magnetic separation was developed that could produce concentrations as high as 70%. Once concentrated, the magnetite grains could then be smelted into various forms of iron. However, the loose, granular nature of the ore was difficult to keep contained in common bloomeries or blast furnaces, having a tendency toward