Amakinite
Amakinite is a rare orthorhombic borate mineral with the chemical formula (Na,K)Fe3+O(SO4). It is a relatively recently discovered mineral, typically found in fumaroles and volcanic environments.
Discovery and Occurrence: Amakinite was first described in 2002 for occurrences on the Tolbachik Volcano, Kamchatka Peninsula, Russia. It is often found as a product of high-temperature volcanic gas activity, specifically within fumaroles. Its formation is associated with the interaction of volcanic gases containing sulfur and alkali elements with iron-bearing materials. Other reported occurrences include locations with similar volcanic activity where appropriate chemical conditions exist.
Physical Properties: Amakinite typically forms as small, platy crystals. It is characterized by its reddish-brown to dark brown color. The mineral exhibits an orthorhombic crystal system. Its hardness is generally low. Specific gravity measurements are around 3.4. Luster is vitreous to dull.
Chemical Properties: Amakinite is a hydrated sodium potassium iron sulfate borate. The chemical formula reflects the variable presence of sodium and potassium. It is often associated with other sulfate and borate minerals. The presence of iron in the ferric state (Fe3+) is a key characteristic.
Diagnostic Features: Distinguishing amakinite from other minerals can be challenging due to its rarity and small crystal size. Microscopic examination, combined with X-ray diffraction analysis, is often required for definitive identification. The combination of its reddish-brown color, orthorhombic crystal system, and association with fumarole environments are key indicators. Its chemical composition, specifically the presence of sodium, potassium, iron, sulfate, and borate, is also critical for identification.
Uses: Due to its rarity, amakinite has no significant industrial or commercial uses. It is primarily of interest to mineral collectors and researchers studying volcanic mineralogy.
Related Minerals: Amakinite is often found in association with other fumarole minerals, including various sulfates, borates, and oxides. These associated minerals provide clues about the conditions under which amakinite formed.