Mesitite

Mesitite is a relatively rare magnesium-rich carbonate mineral belonging to the calcite group. It is chemically a magnesium-iron carbonate, with the formula MgFe(CO3)2. It represents a member of the siderite-magnesite series, where iron (Fe) and magnesium (Mg) substitute for each other in the crystal structure.

Mesitite typically forms as rhombohedral crystals, often massive and fine-grained. Its color can range from yellowish-brown to dark brown, depending on the iron content. It exhibits a vitreous to pearly luster.

Occurrence of mesitite is usually associated with hydrothermal veins, metamorphic rocks (particularly altered ultrabasic rocks), and sedimentary iron deposits. It is often found in association with other carbonate minerals such as magnesite, siderite, dolomite, and calcite.

The origin of mesitite is typically related to the alteration of iron-bearing minerals by magnesium-rich fluids. The iron content in mesitite tends to increase during its formation.

Mesitite has limited industrial uses. It is primarily of interest to mineral collectors and researchers studying carbonate mineralogy and geochemistry. Its relatively high magnesium content could potentially be exploited as a source of magnesium, but other magnesium-rich minerals like magnesite are more abundant and commercially viable.