White crystal group of the very rare borate mineral studenitsite from the type and only known locality worldwide (Pobrdzhsky Potok & Peskanya, Baljevac na Ibru, Jarandol Basin, Raška District, Central Serbia, Serbia). Ex Vandenbroucke Museum collection specimen, from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Studenitsite
A rare dirty-yellow sodium-calcium borate of hardness 6, from Serbian boron deposits.
Intro adapted from Wikipedia (CC BY-SA).
Studenitsite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula NaCa₂B₉O₁₄(OH)₄·2H₂O.
It crystallizes in the monoclinic crystal system (space group P2_1/b).
Key properties: Mohs hardness 5.5–6; specific gravity 2.29; White streak; refractive index 1.545; optically biaxial.
IMA symbol Sdn, IMA status: approved, named in 1994.
Occurs as lenses in clay and carbonate-bearing volcanogenic-sedimentary borate deposits.
It is found associated with Colemanite, howlite, ulexite, pentahydroborite.
The name refers to the Studenitsa Cloister near the first occurrence.