Synthesis of the Humites nMg(2)SiO(4)·Mg(F, OH)(2)

The humite group comprises four minerals having the general formula nMg(2)SiO(4)·Mg(F, OH)(2) where n = 1, 2, 3, and 4. These have been synthesized in the laboratory from melts, by solid state reactions, and by hydrothermal techniques. Complete substitution of GeO(2) for SiO(2) has been accomplished in three of the humites and partial substitution of OH ions for F, Fe for Mg, and Ti for Mg or possibly Si, has been accomplished in one or more of the series. Indices of refraction of the synthetic humites are given and powder X-ray diffraction data have been obtained for the fluorine end members. Also, infrared data from 4,000 to 300 cm(−1) are given for the fluorine end members and these are compared to the corresponding spectra of the natural analogs.