The opaque sample and transparent alexandrite crystals have been analysed by different techniques such as fluorospectrometer, X-ray fluorospeotrometer, ESCA. The measured date support our previous suggestion about the formation mechanism of the melt aging named by Lienard. Then transparent crystal can be grown with good reproducibility. Inolusions and dislocations in the crystals have also been investigated. Since then high quality alexandrite crystals have been grown.