gems, corundum, synthetic corundum.7, Kashan, flux

Synthetic rubies by Kashan are characterized by inclusions of melt residues. Cryolite was used as flux. The inclusions can be divided into four types. Even in samples looking apparently free of inclusions, these inclusions can be found by microprobe analysis (15 samples). The increased amounts of sodium found with the help of neutron activation analysis (NAA) in two analysed samples are caused by these inclusions of cryolite.