Low-iron glass is a type of high-clarity glass that is made from silica with very low amounts of iron. This low level of iron removes the greenish-blue tint that can be seen especially on larger and thicker sizes of glass.Low-iron glass is used for aquariums, display cases, some windows, and other applications where clarity is desired. Low-iron glass typically has a ferric oxide content of about 0.01%. Ordinary plate glass has about 10 times as much iron content. Low-iron glass is made from low-iron silica sand. In the United States, the primary sources for such sand are in Wisconsin.