Introduction:
Among materials used for the fabrication of works of art and of handicraft, gemstones play a peculiar role, since they are often endowed, beyond their historical and artistic interest, with a relevant commercial value. The distinction between more precious gems and simulants, the determination of the origin - synthetic or natural - and the recognizion of possible treatments require non-destructive techniques that should be applicable to both loose gemstones and jewels having any shape and size (Fig.1).
Presentation:
The photoluminescence and reflectance spectra of simple or mixed oxides - such as corundum and spinels - or silicates (e.g. emeralds) or diamonds are determined by the presence of chemical impurities or defects in the crystal lattice. Such features - whether occurring in nature or intentionally introduced - provide information about the story of the object: the most topical issues are diamond synthesis and treatments. Moreover, the vibrational FTIR and Raman spectroscopies are also of great help - in particular in provenance studies - also through the study of inclusions.
The ICIS-CNR, within the investigation of optical properties of inorganic compounds and materials (head of the group: D.Ajò), undertook a study of the spectroscopical behaviour of gemstones, together with activities of synthesis - in particular by the Verneuil method (Fig.2) - and treatments. As a matter of fact, producing knowledge applicable to problems arising from the market implies an active control of the whole process: from raw materials, through possible treatments, to the final produts.
Moreover, while sophisticated and expensive instruments are used in research laboratories for accurate measurements, the demand for low cost and/or portable apparatus is growing: also in this respect, results susceptibile of applications at commercial level were obtained.
Finally, a "pool" of laboratories operanting in CNR Institutes (at Padua, Rome and Florence), University Departments (at Milan, Rome "Tor Vergata" and L'Aquila), and private Institutions (at Padua, Rome and Sesto S.Giovanni) allows extended availability of competences and apparatus (see te ecnlosed document)..
The above activity aroused a relevant interest not only in national and international scientific circles but also, due to evident commercial connections, in those of Public Bodies and Small and Medium Enterpises operating in several Italian Regions. Therefore, is reasonably expected an extension of resources - coming so far e.g. from Agenzia 2000 and "Targeted Project for Special Materials" of CNR, the University and the Province of Padua - to European and Regional funds.
Vedi anche:
Immagini:
