Ultrapotassic igneous rocks

Ultrapotassic igneous rocks are a class of rare, volumetrically minor, generally ultramafic or mafic silica-depleted igneous rocks.

While there are debates on the exact classifications of ultrapotassic rocks, they are defined by using the chemical screens K₂O/Na₂O > 3 in much of the scientific literature. However caution is indicated in interpreting the use of the term "ultrapotassic", and the nomenclature of these rocks continues to be debated, with some classifications using K₂O/Na₂O > 2 to indicate a rock is ultrapotassic.