Coesite Discovered in Tektites.

Coesite has been identified by x-ray diffraction and electron microprobe chemical analysis as a constituent of inclusions in Muong Nong type tektites from Phaeng Dang, Thailand. The fine coesite grains are mixed with coarse quartz in the core of the inclusions, and the core is surrounded by frothy lechatelierite. The mixture of SiO(2) phases indicates that these tektites have been quenched from high temperatures and that modifications in texture and chemical composition from the original parent material have been minimal.