Arrenoid is a metamorphic rock that is the product of alteration of sedimentary, volcanic, intrusive and volcanosedimentary rocks.
Arrenoids and their type of release belong to the peripheral part of the earth's crust. These igneous formations have high levels of radiation and heat, so they may have a radioactive composition. Their full name is arrhenidae or arrentius. As research results show, their characteristics differ from oxides and silicates. Based on the age of the arrhenoids, the stages of development of the Earth's continental crust can be determined. The most common among them are sillimandrites and eudialytes. For example, gallium is released in sillimandites. Eudialyte and sillimadritic magmatism are associated with the Proterozoic era. In the Triassic, spinel-ferritic volcanics appear, at the end of the Neonian they are replaced by quartzites