Study on Hosting State between Calcite and Matrix in Root Amber from Myanmar

This study aims to explore occurrence state of prevalent white vein-like minerals in root amber from Myanmar and their interrelationship with amber matrix. The results of the conventional gemmological tests and Fourier transform infrared spectroscopy (FTIR) confirmed that the yellow-brown matrix of the root amber samples exhibit the typical provenance characteristics of amber from Myanmar. Raman spectroscopic test results identified the white vein-like minerals as calcite and the black granular minerals as pyrite. Optical microscopic and scanning electron microscopic tests provide detailed characterization of the spatial coexistence of the white vein-like calcite and amber matrix. The calcite exhibits an intrusive morphology, interspersed within the internal structure of the root amber matrix, indicating the presence of numerous micron level calcite veins inside the yellow-brown matrix of amber. There is no compositional transition at boundaries between calcite veins and amber matrix. Additionally, the presence of large amounts of broken fragments are observed at the junction between the calcite veins and amber, which could be a potential factor contributing to low transparency of the root amber. The coexistence of calcite as a stable carbon source, with organic amber and pyrite insights into the paleoenvironmental conditions during burial period of root amber.This not only clarifies the formation process of root amber, but also further reflects the historical changes in paleoenvironment.