Results (
English) 1:
[Copy]Copied!
A crystalline element or a solid inorganic chemical compound formed by a geologicalprocess is a mineral and therefore receives a specific name. Natural crystalline aluminum oxide oralumina (α-Al2O3) is named corundum, the monocrystals are colorless and transparent. If theycontain, intimately mixed, microcrystal of magnetite (Fe304) or hematite (Fe203), they are called emery.If the corundum monocrystals contain some elements in isomorphic substitution for Al3+ in theirstructure, gemstones and semi-precious gemstones are formed, also receiving specific names fortheir colors: (a) blue sapphire - blue (Fe, Ti); (b) ruby – red (Cr); (c) yellow sapphire - yellow (Fe3+,Fe2+); (d) purple sapphire - purple (Fe, Mn, Ti); (e) green sapphire – green (Fe2+)[1-4].In natural, color and clarity of sapphires are not popular for market. Generally, the quality ofsapphires may be improved by various processes, one of which is by the thermal process [5].The purpose of this research is to investigate the effects of heat treatment on crystal structures ofcorundum.
Being translated, please wait..