Tarkianite is a rare mineral that belongs to the silicate mineral group. It is named after the Tarkian Mountains in Armenia, where it was first discovered. Tarkianite is characterized by its dark green to black color and is often found in small, prismatic crystal formations.
Chemically, tarkianite is an anhydrous chlorite mineral with the chemical formula (Fe2+,Mg)2Al4Si4O10(OH)2. It has a hardness of 2.5-3 on the Mohs scale, indicating a relatively soft mineral. Tarkianite has a monoclinic crystal system and a platy or flaky habit, with a distinct cleavage perfect in one direction.
In terms of its physical properties, tarkianite is known for its pearly to vitreous luster and its ability to exhibit pleochroism. This means that the mineral may display different colors when viewed from different crystallographic directions. Tarkianite is typically opaque, but thinner crystals may display some transparency.
Tarkianite is primarily found in metamorphic rocks, particularly those associated with regionally metamorphosed limestones or dolomites. It is commonly associated with other minerals such as diopside, grossular garnet, and chlorite. Due to its scarcity and limited commercial applications, tarkianite is primarily valued as a collector's mineral for its aesthetic qualities.
Overall, tarkianite is a dark green to black mineral with a specific chemical composition and unique physical properties. Its rarity and distinctive crystal formations contribute to its desirability among mineral collectors around the world.
