Pyroxene group - Group of minerals that contain iron, magnesium, silicon, and oxygen. They may also contain calcium, sodium, and lithium. The pyroxenes have prismatic cleavage, and one can note the angle of 87° and 93° (almost perpendicular), which distinguishes it from amphiboles which are at 56° and 124°. The pyroxenes are very similar to the amphiboles, and the minerals belonging to each group many times cannot be distinguished by ordinary methods. Generally, though, the pyroxenes occur in shorter, stubbier crystals than the amphiboles. The amphiboles contain the same elements that the pyroxenes do, except they have hydroxyl (OH) in their structure, which alters both its physical and chemical properties.

The pyroxene group is in the inosilicate subdivision of the silicates group.