- The Society of Resource Geology
- 鉱山地質 (ISSN:00265209)
- vol.28, no.152, pp.397-404, 1978-11-01 (Released:2009-06-12)
The minerals of the scheelite-powellite series containing 0, 0.5, 1, 2, 4, 6, 10, 20, 40, 60, 80 and 100 mole % CaMoO4 have been synthesized. The solid solution of this series was obtained by the slow addition of a Na2WO4-Na2MoO4 solution to a large volume of boiling CaCL2 solution. The fluorescent colors of the precipitate change as follows: blue at the scheelite end, pale blue at 0.5 mole % CaMoO4, white at 1 mole %, pale yellow at 2 mole %, and yellow at 4 mole %; and increase yellow tint up to 20 mole %, but do not show any remarkable change beyond that composition. Compared with the standard color card (Fig. 4), on which the precipitates are put, the composition of scheelite containing less than 10 mole % CaMoO4 can be determined within the accuracy of 1 or 2 mole %.The X-ray powder data show that the 2θ 116 (CuKα)-2θ220 (CuKα) values decrease linearly from 5.23° to 4.83° with the increasing amounts of powellite component in this solid solution. Using this value, the composition can be estimated within the accuracy of 10 mole % CaMoO4. From the synthesis, fluorescent colors and X-ray data, it is inferred that the solid solution of the mineral series continues from the scheelite to powellite ends above a room temperature.