Liu Research Laboratories, LLC
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        Gemological Laboratory

        This Laboratory has been engaging in gemological researches, and also provides gemstone identification services. The research projects including identification of treated type IIa diamonds, the diamonds colors caused by plastic deformation with other color centers, the alexandrite effect, colors phenomena in gemstones, fluorescent color of gemstones, advanced digital imaging system for gemstones. We provide GE POL diamond identification, synthetic moissanite identification, jadeite identification, and gemstone identification. We issue gemstone identification report with necessary spectral curve, such as FTIR spectrum for jadeite identification. We include a digital image of the reported gemstone in its report. The digital image can be used as a digital "fingerprint" and saved in our Lab for future rechecking.

Color Grading of Colored Diamonds    We are developing a new precise color grading system for colored diamonds. This system is in the uniform CIELAB color space, and all color grades are basically uniform. A color grade terminology is associate with the system. This system is suitable for both color measurement using spectrophotometers and visual color grading with a color system, such as the Munsell color system, the Natural Color System, or the Pantone color system.

Jadeite Identification service    We currently provide express and extra express jadeite identification service using FTIR and advanced digital imaging system. Customers can obtained identification report in two days for the express service. Upon request with a surcharge, we can also provide extra express one-day service. If a customer submit a sample in early morning, we will issue a report by the end of the same day.
        Our Identification Report including four important sections: Sample Description, Picture, IR Spectrum, and Conclusion. The weight, size, color, cut of a tested sample will be described in the Sample Description section. We have developed an advanced digital imaging system for gem identification. This system can also provide a high resolution digital image, which is usually used for picture in the Report. We will store this digital image as "fingerprint" of the sample for future identity identification purpose. We assign the type of A or B based on the IR spectrum. In the Conclusion section, we will give a precise conclusion without any confusion. 

Grading of the Alexandrite Effect    The alexandrite effect refers to the color change of gemstones under different light sources. It is a non-color-constancy phenomenon. The gemstones with the alexandrite effect are usually more valuable and sought after by collectors. The alexandrite effect has been classified into four categories depending on the hue change under different pairs of light sources. The intensity of the color change can be graded into six grades: non, faint, weak, medium, strong, and very strong.

Color Measurement of Gemstones   Color measurement of gemstones is a difficult task. The face-up color appearance of a faceted gemstone is not uniform, and gemstones are usually transparency. Our Laboratory is doing R&D work to try to solve the problems. We will approach the color measurement by instrument step-by-step. We will study the best measurement geometry, measurement position, the relationships between colorimetric date and visual color appearance under a standard light source. Our goal is to color grading of faceted gemstones by spectrophotometer under a standard geometry and other parameters.

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Copyright © 2003 Liu Research Laboratories, LLC, 2202 Seaman Avenue, South El Monte, CA 91733.
Last modified: August 01, 2005