The Chemical Composition of Trapiche-like Quartz from Huanggangliang Area, Inner Mongolia, China

Abstract

Trapiche-like quartz, which is found in Huanggangliang area, Chifeng City, Inner Mongolia, China, has a short columnar euhedral shape. Arms of trapiche-like phenomena are formed by six radial dark bands located along the a-axis of crystals, and their cores are formed by color zones. Various methods were used to investigate the conventional gemological characteristics, trapiche pattern features, chemical compositions, and spectral characteristics of the trapiche-like quartz. CL images and EPMA results reveal they were formed at high temperature conditions and originated from pegmatite. The hexagonal darker zones with high FeO and very little TiO2 contents indicate the trapiche-like patterns are due to spatial distribution of color-inducing elements. According to the position and interpenetration relationship between inclusions, fibrous and spherical inclusions are identified as protogenetic inclusions, which were respectively identified to be ferro-actinolite and iron oxide by EPMA and Raman spectra.

Keywords

• trapiche-like quartz
• Huanggangliang
• color zones
• inclusions