Pleonaste is a term used in mineralogy to describe a type of iron-rich spinel that is commonly found in igneous rocks. Synonyms for pleonaste include magnetite, hercynite, and ulvospinel. Magnetite is a common mineral that is highly magnetic and often found in deposits that are rich in iron. Hercynite is a black, opaque mineral that is often found in metamorphic rocks, while ulvospinel is a mineral that is commonly found in mafic and ultramafic rocks. Each of these minerals has unique properties and characteristics, making them useful for different applications, including as pigments, catalysts, and abrasives. Understanding the different synonyms for pleonaste can help geologists and mineralogists to better identify and characterize these important minerals.