nagyíta

Nagyíta is a mineral belonging to the plagioclase feldspar group. It is a solid solution series member that falls between the end-members albite (NaAlSi₃O₈) and anorthite (CaAl₂Si₂O₈). Specifically, nagyíta is defined as having a molar composition between 70% and 90% anorthite. Its chemical formula can be represented as (Ca,Na)(Al,Si)₄O₈, where calcium is the dominant cation and sodium is present in smaller amounts.

Nagyíta typically occurs as irregular grains or masses within metamorphic rocks, particularly in high-grade metamorphic environments such as granulites and eclogites. It can also be found in some igneous rocks, especially those that have undergone significant alteration. The color of nagyíta can vary, often appearing white, gray, or pinkish. Its hardness is generally around 6 to 6.5 on the Mohs scale, and it exhibits two directions of perfect cleavage.

The mineral was named in honor of the Hungarian mineralogist and crystallographer, Dr. Miklós Nagy. Its identification and classification are important for understanding the geological conditions under which certain rocks formed, as the composition of plagioclase feldspars can provide clues about the temperature, pressure, and chemical environment of their genesis.