Abstract：As a common mineral, analcime has been widely applying in industry. The compound methodsof analcimearealso mature, but the natural gem-gradeanalcimeis still very rare on Earth. In this paper, the object of discussion is the natural gem-gradeanalcime from the Daye mining area of Hubei province. The purpose is providing its identification and characteristics of origin. These analcimein this area are mostly colorless and transparent, with complete crystal shape and clear crystal surface pattern. The maximum crystal size can reach 36 mm; of course, the clarity of these is excellent too. According to the backscattered electron imagingand energy spectrum analysisresults, determined the crystal is homogeneous analcime. The white inclusion is wairakites with fascicular structure, a set of cleavage and metasomatic relict texture according to the electronic probe microanalyzer results calculation. The characteristics of Raman spectra show that: the diffraction peaks of 81, 139, 201 and 298 cm-1 are caused by the lattice vibration of zeolite. The strong peak of 298 cm-1 may represent the vibration of metal-oxygen. The bending vibration of O—Si—O causes the extremely strong peak of 491 cm-1. The shift of Si—O and AlO tetrahedrons may attribute the diffraction peak of 390, 671 cm-1. A set of peaks at 1 105 cm-1 indicates the stretching vibration of Si—O, which is a typical peak position of natural zeolite. The weak peak of 1 624 cm-1 represents the bending vibration of water, and the strong peak of 3 557 cm-1 represents the stretching vibration of water. The samples' infrared spectra mainly show that: the infrared absorption 788, 1 259 cm-1 are caused by the stretching vibration of silica tetrahedron. The bending vibration of water causes 1 646 cm-1; The weak absorption of 3 635 cm-1 is caused by the tensile vibration of water. For some complete samples, only one absorption can be seen at 3 635 cm-1, which means there is only one form of water molecule in the lattice. In other samples with pocket and chlorite, the 3 635 cm-1 absorptions can be seen on the left side between 3 635 cm-1 with strong absorption, which means the type of water molecules in the lattice are various, and the number is slightly larger than the rest, but still fewer overall. Therefore, according to the composition and spectrumtest, it is speculated that the gem-grade calcite in Hubei Daye belongs to high-temperature sedimentary analcime, which are the metasomatic products of wairakites, and later experienced local chloritization.
Key words：Gem-gradeanalcime; Daye iron ore; Infrared spectrum; Laser Raman spectroscopy
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