Abstract. Pleysteinite, [(H2O)0.5K0.5]2Mn2Al3(PO4)4F2(H2O)10 ⚫ 4H2O, is the aluminium analogue of benyacarite, from Hagendorf-Süd pegmatite, Oberpfalz, Bavaria, Germany. It was found in specimens altered zwieselite, association with nordgauite, fluellite, rockbridgeite, pyrite and columbite. Pleysteinite occurs as isolated small aggregates colourless, stubby prisms that are typically 10 to 30 µ...

Abstract The structure family of the rare‐earth calcium oxoborates O[BO 3 ] (RCOB) has been investigated mainly with regard to their optical characteristics. Due monoclinic‐domatic they exhibit pyro‐ and piezoelectric properties, which is not dependent on numerous possible substitutions cation site R . cations are known show partial disorder earth alkaline positions X Z To study whether a stabi...