IMPURITY SPECIES IN SYNTHETIC AND BRAZILIAN NATURAL QUARTZ

Impurity species in synthetic and Brazilian natural quartz were studied by means of infrared absorption spectroscopy and atomic absorption spectrometry. It is shown that almost all of the Al ions in synthetic quartz are incorporated as a substitutional type of Al(3+). The possibility of the existence of interstitial Al is small. In the formation of Al-related centers in crystals grown in Li-containing solution, the dominant charge compensator for Al(3+) is Li(+). In natural quartz, the charge of Al(3+) is compensated by Li(+) and H(+) to form Al-Li and Al-OH centers. Na(+) ions are incorporated into crystal with H2O impurities both in synthetic and natural quartz. The content of Al-hole centers due to gamma irradiation is approximately proportional to the content of Al-Li centers and inversely proportional to H2O impurity content.