"Ironstone," Buddha from around 1900-1920, entirely handmade.

Ironstone is a sedimentary rock that is either directly deposited as an iron-rich sediment or formed by chemical replacement and that contains a substantial amount of an iron ore compound from which iron (Fe) can be commercially smelted. Not to be confused with native or telluric iron, which is very rare and occurs in metallic form, the term ironstone is usually restricted to hard, coarsely banded, unbanded, and non-chert-like sedimentary rocks of post-Precambrian age. The Precambrian deposits, which have a different origin, are commonly known as banded iron formations. The iron-bearing minerals that form ironstones can consist of oxides, such as limonite, hematite, and magnetite; carbonates, such as siderite; silicates, such as chamosite; or a combination of these minerals.