Studenitsite is a rare borate mineral

Borate mineral

The borate minerals are minerals which contain a borate anion group. The borate units may be polymerised similar to the SiO4 unit of the silicate mineral class. This results in B2O5, B3O6, B2O4 anions as well as more complex structures which include hydroxide or halogen anions...

 with chemical formula of NaCa₂[B₉O₁₄(OH)₄]·2H₂O.

Studenitsite has a vitreous luster, a Mohs hardness of 6 and color of light-dirty yellow. It is a monoclinic mineral and belongs to the space group P2/c. The basic unit of the crystal structure[B₉O₁₄(OH)₄]5-layers has a Miller Index of (001). Studenitsite has a low surface relief which means the measure of the relative difference between the index of refraction of the mineral and surrounding medium is small. Birefringence is the difference between two principal indices of refraction of a uniaxial crystal. Studenitsite has a maximum birefringent value of δ = 0.032. Studenitsite has three indices of refraction. Their values are nα = 1.532 nβ = 1.538 nγ = 1.564. Indices of refraction are the ratio of the light's speed in the mineral and the medium.

Studenitsite is a extremely rare mineral that has only been found in the Piskaya deposit, Yarondolskii Basin, on the Ibar River

Ibar River

The Ibar is a river that flows through eastern Montenegro and Serbia, with a total length of . The river begins in the Hajla mountain, eastern Montenegro, passes through Kosovo and flows into the West Morava river, Central Serbia, near Kraljevo....

, 280 km south of Belgrade

Belgrade

Belgrade is the capital and largest city of Serbia. It is located at the confluence of the Sava and Danube rivers, where the Pannonian Plain meets the Balkans. According to official results of Census 2011, the city has a population of 1,639,121. It is one of the 15 largest cities in Europe...

, Serbia. The deposit is classified as a volcanogenic-sedimentary borate deposit with clay

Clay minerals

Clay minerals are hydrous aluminium phyllosilicates, sometimes with variable amounts of iron, magnesium, alkali metals, alkaline earths, and other cations. Clays have structures similar to the micas and therefore form flat hexagonal sheets. Clay minerals are common weathering products and low...

 and carbonate minerals. It occurs associated with colemanite

Colemanite

Colemanite is a borate mineral found in evaporite deposits of alkaline lacustrine environments. Colemanite is a secondary mineral that forms by alteration of borax and ulexite....

, howlite

Howlite

Howlite, a calcium borosilicate hydroxide , is a borate mineral found in evaporite deposits. Howlite was discovered near Windsor, Nova Scotia in 1868 by Henry How , a Canadian chemist, geologist, and mineralogist. How was alerted to the unknown mineral by miners in a gypsum quarry, who found it...

, ulexite

Ulexite

Ulexite , sometimes known as TV rock, is a mineral occurring in silky white rounded crystalline masses or in parallel fibers. The natural fibers of ulexite conduct light along their long axes, by internal reflection...

 and pentahydroborite. It is a rare but important mineral for understanding the volcanic settings in Western Serbia. It was named after the Studenica

Studenica monastery

The Studenica monastery is a 12th-century Serbian Orthodox monastery situated 39 km southwest of Kraljevo, in central Serbia. It is one of the largest and richest Serb Orthodox monasteries....

 cloister

Cloister

A cloister is a rectangular open space surrounded by covered walks or open galleries, with open arcades on the inner side, running along the walls of buildings and forming a quadrangle or garth...

near the discovery location.