Ferrohortonolite

Ferrohortonolite is a rare mineral belonging to the amphibole group, characterized by its complex chemical composition and distinctive physical properties. It was first discovered in the Horton Bluffs region of Antarctica and is named after this location. The mineral is typically found in metamorphic rocks, often associated with other amphibole minerals such as hornblende and actinolite.

Ferrohortonolite exhibits a dark green to black color, with a vitreous to dull luster. Its crystal system is monoclinic, and it commonly forms prismatic crystals or granular aggregates. The mineral's hardness on the Mohs scale is approximately 5 to 6, and its specific gravity ranges from 3.2 to 3.4.

The chemical formula of ferrohortonolite is (Ca2.5)(Fe2+2.5Fe3+0.5)(Mg3.5Fe2+0.5)Si8O22(OH)2. This complex composition reflects the mineral's amphibole structure, which consists of double chains of silica tetrahedra linked by octahedral sites occupied by various cations, including calcium, iron, and magnesium.

Ferrohortonolite is of interest to mineralogists and geologists due to its rarity and the insights it provides into the geological processes that form amphibole minerals. Its discovery and study contribute to a better understanding of the complex mineralogy and petrogenesis of metamorphic rocks.