TREATMENT: There are several treatments for Padparadscha. Synthetic padparadscha sapphire crystals grow submerged in a slowly cooling high-temperature liquid and have unusually high perfection and very good brilliance when cut or faceted to make loose gemstones.Sometimes they are produced by beryllium diffusion: usually shows a yellow-orangy rim – pink core when immersed. Radioactive bombardment is used much less often for strengthening the yellow colour of sapphire and the creation of an orange tint in pink chromium-rich stones, which is characteristic for padparadscha sapphires.Verenuil Or Flame fusion is one of the first methods used to produce synthetic gemstones, initially for corundum, thereafter for a number of other gemstones.
This method is based on the melting of very finely pulverized alumina in an oxy-hydrogen blowpipe type burner. This requires a highly purified alumina which is prepared by repeated crystallization and later calcination of ammonium alum. The alumina is placed in a container or hopper which is tapped from above by a hammer at regular pre-selected intervals and regulates the flow of powder. This powder drops through the oxy-hydrogen flame, melts and falls on a rotating pedestal, where it solidifies. This pedestal is lowered slowly to allow cooling and crystallization of the corundum boule. The flame temperature generally ranges from about 1000☌ to 2400☌ since the melting point of corundum is approximately 2050☌. The different varieties of corundum are obtained by adding various metallic oxides to the alum before it is calcined.īoth the growing crystal and the flame are protected from temperature variations by a circular ceramic heat resistant walled area.
0 kommentar(er)
