sordit

Sordit is a fictional mineral used in geology education to illustrate mineral classification, crystallography, and geochemical substitution. It is not recognized by major mineral databases or the International Mineralogical Association, and has no verified natural occurrence outside teaching materials.

Etymology and naming: The name combines the fictional region of Sordia with the common mineral suffix -it. In diagrams and problems it is often depicted with a dull olive-green to gray color to reflect a typically weathered appearance.

Properties: Sordit is described as monoclinic, crystallizing in short prismatic crystals up to several centimeters. It has a Mohs hardness of about 5.5–6 and a specific gravity around 3.3–3.6. The color ranges from olive-green to gray; the streak is gray-black and the luster ranges from metallic to submetallic. The empirical formula is given as (Fe,Mg)2SiO4 with trace Cu and Al substituents, enabling discussion of solid-solution behavior between iron-magnesium and copper-bearing end members.

Formation and occurrence: In educational material, sordit forms during high-temperature metamorphism of iron-rich sediments in a subduction-zone setting and is described as occurring within schist or gabbroic rocks alongside magnetite and olivine.

Uses and significance: Sordit serves as a teaching tool to illustrate mineral properties, crystallography, and the effects of trace-element substitution. It is used in problem sets and textbooks to demonstrate how composition affects color, density, and hardness in silicate minerals.

See also: Silicate minerals and Mineral classification.