СЕРИЯ САДАНАГАИТА В ИЛЬМЕНОГОРСКОМ ЩЕЛОЧНОМ КОМПЛЕКСЕ (УРАЛ, РОССИЯ)

Abstract

On the base of Nomenclature for the amphibole group minerals approved by the CNMMN IMA in 1997 and a matrix model of the amphibole nomenclature, an analysis of published data has been carried out for amphiboles of sadanagaite series from various regions over the world (Russia: Transbaikalia and Il'menskye Gory; Japan: Yuge and Miodzin islands; Austria: the Alpes: Sardinia). Amphiboles of the sadanagaite series are characterized by the following crystal-chemical formula: R1+R2 2+(L3M2)(Si5Al3)022(D-)2. It has been revealed that at present there arc known 6 final members of this series. Among them, two are normative ones (Na prevails over К in the A position): sadanagaite and alumino-magnesiosadanagaite. Such members as aluminosadanagaite and magnesiosa-danagaite are actually unknown yet. Four other members are the potassium analogs (K prevails over Na): potassiumsadanagaite. potassic-aluminosadanagaite. potassic-magnesiosadanagaite, and potassic-alumino-magnesiosadanagaite. Three final members have been found within Il'menogorsky alkaline complex; two among them are normative ones: sadanagaite and alumino-magnesiosadanagaite. the third one is the K-analog - potassicsadanagaitc. Sadanagaite and potassicsadanagaite are known in the Il'menogorsky complex only; their analyses have been published for the first time in 1974 but attributed by the author as hastingsite. So, «sadanagaite» was discovered in 1986 in Japan, where all its finds are represented by potassic analogs.