Study On Mineralogical Character Of Tinea On The Weathering Crust Of Feicui

As the king of jade, Feicui is one of the most delighted and profitable jade. Green Feicui is most valuable. The different size and shape of balck and dark green imprint on the weathering crust of the Feicui raw material is named tinea. The tinea is undesirable, but its output and sharp has important indications to the green deep in Feicui. Based on the preresearch, the author study the tinea's composition and structure by Microscope, EMPA, XRD, FITR, Ramman, SEM means in this paper.The result implies that the tinea is composed of amphibole, most belongs to sodic and sodic-calcic amphibole. The structure of tinea is compact observed from SEM. Mineral grain is prismy and fibrous. Based on the observation from Microscope, the cause of the formation of amphibole is discussed, and can be divided in two groups. The relationship of tinea and green can be described as'tinea ate green'and'tinea sprayed green'. We can predicate the green of Feicui according the texture of Feicui and the shape of tinea. Based on the crystal lattice of amphibole, the phenomena'thnea sprayed green'can be explained as the Cr3+ can only occupy the position of M2 and can not occupy the other position in the crystal lattice."glimmering"FeiCui has a high value, but fewer researches related to this topic have been conducted for past few years through detailed literature review. In this paper, the optical principle and cutting methods are studied by using the texture of Feicui. The results shown that the necessary factors of"glimmering"FeiCui formation:1. globoidal cutting or globoidal cutting partly; 2. perfect polishing; 3. Basic mineral particles in the 0.05 to 0.14 mm range; 4. Polycrystalline quality aggregates.