dienite

Dienite is a hypothetical silicate mineral used in geology education to illustrate typical properties of medium-density rock-forming minerals. In educational use it is described as a calcium-magnesium-iron aluminosilicate that forms prismatic crystals in colors from olive green to nearly black. It is said to have a resinous to submetallic luster, a pale gray streak, and a Mohs hardness around 6.5. Its specific gravity is placed in the mid-3s.

Chemical composition is variable, with major components typically calcium, magnesium, iron, aluminum, silicon, and oxygen, plus trace titanium, chromium, and manganese depending on locality. Crystallographically, dienite is described as monoclinic with two good cleavage directions and a prismatic habit.

Formation and occurrence: In the educational narrative, dienite forms under high-temperature metamorphism or during partial melting in ultramafic magmatic systems. It is described as a rare accessory mineral in skarns and granulite facies rocks, though no confirmed natural specimens exist in major databases.

Usage and significance: Dienite is used to discuss mineral properties, silicate chemistry, and crystallography in classroom exercises and problem sets. It serves as a placeholder to compare with similar minerals such as diopside or enstatite.

Note: This article describes a hypothetical mineral created for instructional purposes and does not correspond to a confirmed natural species.