Amethyst and morion quartz gemstone raw materials from Turkey: color saturation and enhancement by gamma, neutron and beta irradiation (original) (raw)
Related papers
An Update on Color in Gems. Part 1: Introduction and Colors Caused by Dispersed Metal Ions
Gems & Gemology, 1987
Studies concerning the origin of color in gem materials have grown i n sophistication in recent years, so that much new information is now available about natural color and its possible modification b y various treatment processes. This three-part series of articles reviews our current understanding of gemstone coloration. The first part summarizes the factors that govern the perception of color, from the source of light to the human eye, and then examines in detail the role of one color-cozising agent, dispersed metal ions, in the coloration of many gem materials, including ruby and emerald. The second part will explore charge-transfer phenomena and color centers as the cause of color in gems such as blue sapphire and Maxixe beryl. The series will conclude with colors that can be explained usjng band theory and physical optics, such as the play-of-color in opal and the blue sheen of moonstone feldspars.
An experience of electron beam (EB) irradiated gemstones in Malaysian nuclear agency
2014
In Nuclear Malaysia, a study on gemstone irradiation using beta particle is conducted. The purpose of the study is to evaluate the gemstone colour enhancement by using different kind of precious and non-precious gemstones. By using irradiation technique, selected gemstones are exposed to highly ionizing radiation electron beam to knock off electrons to generate colour centres culminating in the introduction of deeper colours. The colour centres may be stable or unstable depending on the nature of colour centre produced. The colour change of irradiated stones were measured by HunterLab colour measurement. At 50 kGy, Topaz shows changes colour from colourless to golden. Meanwhile pearl shows changes from pale colour to grey. Kunzite and amethyst shows colour changes from colorless to green and pale colour to purple. Gamma survey meter measurement confirmed that irradiation treatment with 3 MeV electron beam machine does not render any activation that activate the gems to become radioactive.
Atoms for Peace: an International Journal, 2009
Four Cs namely color clarity carat (weight) and cut primarily determine the price of a gem. Neutron irradiation, gamma rays and electron beam can be utilized to enhance the color and clarity of aquamarine, quartz, tourmaline, kunzite, topaz, pearls and most importantly of diamonds. Imparting color and clarity to these gems, otherwise devoid of these attributes, results in significant value addition. The enhanced gems may possess stable or unstable colors depending on the nature of color centre produced. This paper reviews the processes of enhancement of topaz and diamonds with special emphasis on neutron irradiation. In view of the radioactivity generated as a result of exposure to neutrons and the likelihood of undue exposure to radioactive gems, safety aspects have been discussed. From commercial viewpoint the aspect of detection of treated material has been documented. Related contender, the process of enhancement of gems by gamma rays has been described. The enhancement of gems by radiation (in synergy with heat) is a commercially viable technique and constitutes a peaceful application of nuclear technology .It has potential and future prospects in GCC member states.
CONTRIBUCIONES A LAS CIENCIAS SOCIALES
The present work refers to a study on the production of dimension stones slabs with hyaline quartz and its potential for color development through irradiation combined with heat treatment. The research included technical visits to a company that produces slabs (combining parts of sliced quartz crystals) for the dimension stone industry, where the stages of slabs production were described. The material used was classified as a colorless hyaline quartz, with the presence of partially healed fractures and monophasic fluid inclusions, that need more attention when in the heat treatment. The study evaluated the potential for color development through combined irradiation and thermal treatments, using analyses at the Federal University of Espirito Santo - UFES gem and characterization laboratory and at the infrared spectroscopy laboratory at the Nuclear Technology Development Center - CDTN. The results showed that hyaline quartz fragments can develop characteristic colors depending on the...
Analysis of Selected Gemstones
Gemstones are valued for their natural beauty, and often their interesting colors. In this laboratory experiment gemstones were analyzed for first their genuineness and second their chemical composition with respect to color to see how they correspond. In doing so it was discovered that silicon atoms are highly reflective and that microscopic grain boundaries are not the same as macroscopic color boundaries. Macroscopically smooth boundaries may be very rough microscopically, though more work is needed to verify this observation.
Gem Diamonds: Causes of Colors
Diamonds for gem use are colorless in general, but some stones with bright colors are highly valued as fancy color diamonds. The body color of diamond depends on the concentration of nitrogen and the form of aggregation. Structural defects and vacancy bonding may also cause color centers. Furthermore, plastic deformation may bring has been carried out on a commercial basis. The combined process of electron beam irradiation with annealing and the high-pressure high-temperature (HPHT) process are quite common treatment techniques today. Leading gem laboratories around the world are currently working on these tasks to establish techniques, with a few exceptions, for revealing the origin of the color of the diamond.
Production of Radioactive Gemstones
The possibility of making precious stones from radioactive waste is being considered. Vitrified and cemented radioactive waste (RW) is considered as an artificial rock belonging to aluminosilicates and calcites. Two methods are proposed for the manufacture of radioactive gemstones from RW and their subsequent storage with the possibility of sale, resale, inheritance, and so on. That is, RW is considered as real estate in which capital can be invested. After decontamination in hundreds and thousands of years, it will be of scientific, historical, jewelry interest.
Using SIMS to diagnose color changes in heat treated gem sapphires
Applied Surface Science, 2004
In early 2002, a large number of orange colored sapphires began to appear in the gem market and showed clear evidence of being treated by bulk/lattice diffusion of a surface impurity element. Initial analyses of these stones using EPMA and LA-ICP did not indicate any difference between the center of the stone and the colored rim. However, mass spectral analysis of the cores and rims of these stones using SIMS detected a higher Be content in the colored rims. Subsequent experimental work has shown that diffusion of Be into the sapphires within a controlled oxygen atmosphere is the cause of the color change. We have now calibrated 14 elements by using ion-implanted semiconductor-grade sapphire standards. All measurements have been done using a PHI 6600 quadrupole SIMS instrument. Repeat analyses of the implanted reference material show a relative standard deviation of 8.5% for Be and 12% for Fe. By using a low beam current and small raster, the analysis crater is practically invisible on faceted stones, in contrast to laser ablation shots in the LA-ICP. Use of the quadrupole instrument makes charge compensation easy and the ability to tilt the stage makes alignment of small facets possible. A background of about 0.6 ppm wt. is caused by interference from Al 3þ for Be.
GEMSTONE ENHANCEMENT AND DETECTION IN THE 1990 S By
Gemstone enhancements and their disclosure became the most important gemological issue for the jewelry trade in the 1990s. Growing public awareness of treatments and the greater use of sophisticated technology to enhance the color and/or apparent clarity of gem materials brought to the forefront the need to maintain (or in some cases regain) the consumer confidence that is so vital to this industry. The treatments with the greatest impact were those that affected the gems that were commercially most important: heat and diffusion treatment of ruby and sapphire, "oiling" of emeralds, and fracture filling of diamonds. At the end of the decade, the decolorization of diamonds by high pressure and high temperature posed one of the greatest identification challenges ever faced by gemologists worldwide. Yet most other gem materials were also subjected to enhancements-ranging from traditional processes as with quench-crackled quartz to novel "impregnation" techniques such as the Zachery treatment of turquoise. This article discusses the treatments that were new or prominent during the '90s and suggests methods for their detection.