Cornish words and phrases

thumb|Azurite-[[malachite on gossan from Arizona]] thumb|Malachite on gossan from Australia Gossan (eiserner hut or eisenhut) is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein. In the classic gossan or iron cap all that remains is iron oxides and quartz, often in the form of boxworks (which are quartz-lined cavities retaining the shape of the dissolved ore minerals). In other cases, quartz and iron oxides, limonite, goethite, and jarosite, exist as pseudomorphs, replacing the pyrite and primary ore minerals. Frequently, g

thumb|This vug in the Cascade Range is partially filled with [[quartz crystals.]]