抄録
Nepheline was found in contaminated rocks accompanied with the gehlenite-spurrite skarns at Kushiro, Hiroshima Prefecture. The mineral occurs as a main rock forming mineral up to 2mm wide, associated with clinopyroxene, potash feldspar, titanite and apatite. It is hexagonal with the unit cell dimensions: a=9.986 (3), c=8.372 (3) A. Optically, it is uniaxial negative with refractive indices ω=1.534 and ε=1.528. Vickers microhardness is 634-762 kg/mm2 (100g load) and observed density is 2.63g/cm3. The average chemical composition of the mineral is FeNe1.3 Ne70.5Ks21.3An2.0Q4.9. Chemical composition is not variable.
The nepheline-bearing contaminated rocks are thought to have been derived by local desilication of quartz monzonitic magma.
