The existences of both synthetic diamonds and treatments that can change the color of a diamond justify fundamental research in order to deliver a reliable and high quality certificate. Research on stones has to be reproducible, fast and – of course – non destructive. Optical spectroscopy complies with these conditions and is therefore intensively used in diamond research. Different optical spectroscopic techniques have in common.
- light of a certain color falls on the diamond.
- after interaction of this light with the diamond, it is captured and split into different colors.
- the detector registers the intensity of light as a function of the color (wavelength).
- software visualizes data and allows data processing to get specific information.
Types of Instruments:
- UV-Vis absorption spectroscopy: Light is a wave and each color of the spectrum corresponds to a specific wavelength. This is expressed in nanometer (nm). Visible light exists of the different colors of the rainbow (red, orange, yellow, green and blue, violet). Color in diamond is generated when some colors of the rainbow are absorbed more than others. UV-Vis spectroscopy is used to examine how Ultra Violet (UV) and visible (Vis) light interact with diamond. For each wavelength the percentages of light being transmitted and absorbed are measured.
- Infrared absorption spectroscopy: Determination of the type of diamond can be performed with the aid of infrared spectroscopy. This method is applicable for both rough and polished stones, and gives a spectrum fast (< 2 min).
- Photoluminescence: Contrary to UV-Vis and Infrared absorption spectroscopy, photoluminescence on diamond uses only laser light of one single color (wavelength). This incident light may excite fluorescence colors with a longer wavelength. Incident green light may cause for example the diamond to radiate red light. Incident ultraviolet light may make some diamonds to radiate blue or green light. From the analysis of this excited light, information may be obtained on the presence of for example nitrogen defects in the diamond. This information helps the decision-making whether the diamond is HPHT treated to enhance its color.
- D-Screen: To support confidence in diamond, HRD - Antwerp World Diamond Center developed the D-screen. This instrument distinguishes polished colorless or near colorless diamonds that are neither synthetic nor color enhanced with techniques known today, from diamonds that require additional sophisticated tests for identification in a grading lab. The color range for polished diamonds eligible for testing is D to J. The measurements are based on the optical transmission through the polished stone at deep UV wavelengths.
- Pocket size: 4x5x15cm
- For polished stones from 0.2ct to 10ct
- Can be used at the office (mains powered) as well as out of office (battery)
- Ergonomic set-up: easy positioning of loose stones on table.
- To buy D-Screen instrument visit http://www.comdiam.com/dscreen.htm
- DiamondSure™: The Diamond was developed by DTC (Diamond Trading Company) Research Center. It is a screening device to discriminate natural diamond from synthetic diamond and diamond stimulants.
The DiamondSure™ determines whether a polished stone is definitely a natural diamond or requires a further test to establish its identity. The test is done in a few short steps: the polished stones are placed table down on a measurement probe, a test button is pressed and the visible absorption spectrum of the stone is measured and analyzed with proprietary software.
- To buy DiamondSure™ instrument visit http://www.giainstruments.co.uk/
- DiamondView™: The DiamondView was developed by DTC (Diamond Trading Company) Research Center. DiamondView™ is a perfect complement to screening instruments.
Questionable diamonds that require testing beyond the capability of a screening device can be analyzed and identified with DiamondView™. DiamondView™ works by producing a fluorescence image of a polished diamond. Specifically, DiamondView™ uses a camera to display the fluorescence pattern created on the surface of a polished diamond after it has been exposed to shortwave UV light. Given that the fluorescence patterns from high temperature grown synthetic diamonds differ greatly from those of natural diamonds. DiamondView™ makes it possible for jewelry professionals to ascertain whether a diamond is natural or man-made. In addition, by recording a phosphorescence image, DiamondView also makes it easy to detect whether type II types diamonds could be near colorless synthetics.
- To buy DiamondView™ instrument visit http://www.giainstruments.co.uk/
Jewellery is one of the most bought products online. An estimated $1 billion USD of diamonds are bought annually via the Internet. Over 40 million people use the Internet to trade!