Asterism can be produced by engraving metal foils or plates on doublets to imitate popular gemstones with stars. To imitate the phenomena silver, copper, brass or steel may be used as metal backings on doublets by scratching three sets of parallel lines sets of lines or grooves, using emery or carborundum paper. Other variations include scratched metal foils as backings to create four or six-rayed stars or metal foils with a network of engraved or impressed lines, along with a protective third layer of plastic or mineral. A good example is synthetic blue spinel triplet with a middle layer of engraved metal foil.
For well informed buyers, if the gemstones are unset identification is not difficult. The first hint is the color, diffused asterism and physical appearance.
No comments:
Post a Comment