Topic
Gemstone
About: Gemstone is a research topic. Over the lifetime, 286 publications have been published within this topic receiving 2217 citations. The topic is also known as: gem & jewel.
Papers published on a yearly basis
Papers
TL;DR: Two other groups of materials based on carbon, namely the fullerenes and graphines have been identified in recent years and are now the subject of intense research.
Abstract: Diamond is an exciting material with many outstanding properties; see, for example Field J E (ed) 1979 The Properties of Diamond (London: Academic) and Field J E (ed) 1992 The Properties of Natural and Synthetic Diamond (London: Academic). It is pre-eminent as a gemstone, an industrial tool and as a material for solid state research. Since natural diamonds grew deep below the Earth's surface before their ejection to mineable levels, they also contain valuable information for geologists. The key to many of diamond's properties is the rigidity of its structure which explains, for example, its exceptional hardness and its high thermal conductivity. Since 1953, it has been possible to grow synthetic diamond. Before then, it was effectively only possible to have natural diamond, with a small number of these found in the vicinity of meteorite impacts. Techniques are now available to grow gem quality synthetic diamonds greater than 1 carat (0.2 g) using high temperatures and pressures (HTHP) similar to those found in nature. However, the costs are high, and the largest commercially available industrial diamonds are about 0.01 carat in weight or about 1 mm in linear dimension. The bulk of synthetic diamonds used industrially are 600 µm or less. Over 75% of diamond used for industrial purposes today is synthetic material. In recent years, there have been two significant developments. The first is the production of composites based on diamond; these materials have a significantly greater toughness than diamond while still maintaining very high hardness and reasonable thermal conductivity. The second is the production at low pressures by metastable growth using chemical vapour deposition techniques. Deposition onto non-diamond substrates was first demonstrated by Spitsyn et al 1981 J. Cryst. Growth 52 219–26 and confirmed by Matsumoto et al 1982 Japan J. Appl. Phys. 21 L183–5. These developments have added further to the versatility of diamond. Two other groups of materials based on carbon, namely the fullerenes and graphines have been identified in recent years and are now the subject of intense research.
206 citations
Patent•
14 Nov 1997
TL;DR: Synthetic gemstones are produced by growing single crystals of silicon carbide, fashioning the carbide into gemstone cores, and thereafter depositing a thin coating of diamond on the core as mentioned in this paper.
Abstract: Synthetic gemstones are produced by growing single crystals of silicon carbide, fashioning the silicon carbide into gemstone cores, and thereafter depositing a thin coating of diamond on the core.
166 citations
TL;DR: In the classic model, Be-bearing pegmatites interact with Cr-bearing ultramafic or ma�c rocks as discussed by the authors, and it has been demonstrated that circulation processes within the host black shales were sufficient to form emerald.
122 citations
TL;DR: A review of the use of laboratory Raman and micro-Raman spectrometers and of portable Raman systems in the gemology field is given, focusing on gem identification and on the evaluation of the composition, provenance, and genesis of gems.
Abstract: Being nondestructive and requiring short measurement times, a low amount of material, and no sample preparation, Raman spectroscopy is used for routine investigation in the study of gemstone inclusions and treatments and for the characterization of mounted gems. In this work, a review of the use of laboratory Raman and micro-Raman spectrometers and of portable Raman systems in the gemology field is given, focusing on gem identification and on the evaluation of the composition, provenance, and genesis of gems. Many examples are shown of the use of Raman spectroscopy as a tool for the identification of imitations, synthetic gems, and enhancement treatments in natural gemstones. Some recent developments are described, with particular attention being given to the semiprecious stone jade and to two important organic materials used in jewelry, i.e., pearls and corals.
108 citations
TL;DR: In this paper, the authors summarized the factors that govern the perception of color, from the source of light to the human eye, and examined the role of dispersed metal ions in the coloration of many gem materials, including ruby and emerald.
Abstract: Studies concerning the origin of color in
gem materials have grown in sophistication
in recent years, so that much new information
is now available about natural
color and its possible modification by 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-causing 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 using band
theory and physical optics, such as the
play-of-color in opal and the blue sheen
of moonstone feldspars.
99 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 7 |
| 2020 | 8 |
| 2019 | 11 |
| 2018 | 10 |
| 2017 | 15 |
| 2016 | 10 |