Structural state of adularia from Hishikari, Japan

Adularia sample was collected front epithermal Au-, Ag-bearing quartz-adula ria veins from Hishikari, Japan, This adularia is rich In K, Or=93.63, clea r, transparent, fine-grained and closely associated with quartz. In this st udy, it was determined by XRD, IR and Si-29, Al-27 MAS NMR methods. The adu laria studied is of high sanidine with triclinic domains in it. The occupan cy of Al 2t(1)=0.60, IR ordering theta =0.15. Si-29 NMR spectrum of this ad ularia shows a broad triplet peak, i.e, 3 poorly separated peaks at -94.9, -96.7, -99.9. This kind Si-29 NMR spectrum for natural high sanidine has ne ver been reported before. And the Al-27 NMR spectrum gives an asymmetry pea k with chemical shift at 58.7 extending slightly to the low frequency. Unde r a violent boiling environment, Hishikari adularia rapidly crystallized fr om a supersaturated solution.