抄録
As a general rule, the gemstones in the ordinary jewelry trade are judged by the technique with unaided eye, and the so-called 'basic judg-ing method' based on the gemmology. Most gemstones can be judged by such a technique on the judging method. However, gemmologists sometimes encounter such gemstones which is not easy to judge. In recent years, because of technical process in making synthetic or man-made stones and diversification of making such stones, we meet more often than ever before such cases where we find it extremely difficult to distinguish between natural stones and imitations. Therefore, the introduction of new instruments and testing methods for the identification of gemstones in the jewelry trade was seriously discussed. Already some new analyzing techniques, using, for instance, flourescent X-ray, ultra violet, infrared and visible ray, are being employed by some gemologists. However, these new instruments are unfortunately too expensive to come into general use and are not as effective as one expected. In spite of these difficulties, the gemologists should promote utilization of new instruments since these methods are particularly useful in identi-fing some gemstones. It is the most important in the jewelry trade to become proficient in gemtesting with unaided eye and the simple methods based on gemmology. It may be said that the development of these technique and the basic instrumentation are the most important things we have to learn in the trade today.
