Kaolinized

Part of speech: adjective

Definitions

1. The alteration of mineral substances into kaolin occurs through a process involving chemical changes
2. This transformation refers to the conversion of certain minerals into kaolinite clay through specific geological processes
3. Changed by chemical weathering to form kaolinite clay from original minerals

Etymology: Kaolinite takes its name from Kao-ling, a hill near Jingdezhen in China's Jiangxi province, where the white clay used in fine porcelain was dug. European traders brought the term west, and the mineral was named for that hill, while "kaolin" became the general word for the clay itself. "Kaolinized" is simply the past participle of "kaolinize," a verb formed by adding the suffix "-ize," meaning "to make or become," to "kaolin." So a rock described as kaolinized has been transformed into kaolin. The change happens through chemical weathering. Water, often slightly acidic and carrying dissolved carbon dioxide, slowly attacks feldspar and other aluminum silicate minerals, stripping out alkali metals and silica. What remains is the fine, platy clay mineral kaolinite. The process can be seen in granite and other rocks that have been altered by hydrothermal fluids or long exposure to tropical conditions, where the original crystals are replaced by soft, white clay.