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Unakite is a metamorphic rock that is altered granite composed of pink orthoclase feldspar, ... First found in the United States, unakite has a worldwide distribution
Unakite was first discovered in the Unaka Range, and was named after it. Unaka Mountain Wilderness. Established in 1986 by the U.S. Congress, ...
Unakite – Multicoloured metamorphic rock – An altered granite; Variolite – Igneous rocks which contain varioles; Vogesite – Type of ultrapotassic igneous rock – A variety of lamprophyre; Wad (mineral) – Porous secondary manganese oxyhydroxide – A rock rich in manganese oxide or manganese hydroxide
Unakite; Chatoyant gems. Some minerals made into gemstones may display a chatoyancy or cat's eye effect, these include: [1] Actinolite; Andalusite; Apatite; Beryl.
Cerro Mackay, a mountain in Coyhaique in Chile, made of columns of adakite [1] Closer view of the adakite columns of Cerro Mackay, Chile. Adakites are volcanic rocks of intermediate to felsic composition that have geochemical characteristics of magma originally thought to have formed by partial melting of altered basalt that is subducted below volcanic arcs. [2]
It was first found in the granite of east Greenland and described by Thomas Allan in 1808, after whom the species was named. Allanite is a mineral readily altered by hydration, becoming optically isotropic and amorphous : for this reason several varieties have been distinguished, and many different names applied.
It is often found in minute micaceous aggregates (with individual plates barely visible), as a major component of chromium rich phyllitic or schistose metamorphic rocks of the greenschist facies. Verdite is a type of metamorphic rock made mostly of an impure, often multicolored, variety of fuchsite. It is used for ornamental carvings.
[11] [12] The variation found in some eclogite xenoliths at the Roberts Victor kimberlite pipe are a result of hydrothermal alteration of basalt on the seafloor. [11] This process is attributed to both low- and high-temperature seawater exchange, resulting in large fractionations in oxygen isotope space relative to the upper mantle value ...