Emerald gemology detection method

For consumers, coated jade may be difficult if viewed with the naked eye. Experienced appraisers can find clues of lacquered jade from the subtle external features and touch in the hands. With the advanced detection instruments such as infrared spectroscopy and laser Raman spectroscopy of NGTC Gem Laboratory, the traces of laminating treatment are even more Nothing to do, so the fake will never be true.

Magnification detection: using a magnifying glass or gem microscope to observe the film jade is often seen with small friction marks (small knife can be drawn), no jade features, green is only attached to the epidermis (membrane) of jade jewelry, not from the interior of the jade, due to The adhesion is not strong, and the advantage is also the unbonded part between the film and the jade.

When the film jadeite is observed by laser confocal microscopy, the difference in surface characteristics between the film and the jade can be clearly distinguished, and the thickness of the film "Jade" can be quantitatively measured. When the coated jadeite sample is enlarged to 240 times, it can be clearly seen that the surface features of the film are significantly different from the surface features of the jade, and irregular scratches appear on the surface of the film, on the surface of the jade. This kind of scratch is not allowed. The thickness of the "film" was measured by a quantitative measurement system of a laser confocal microscope to be generally 16 μm.

Feel: The film jade has a feeling of sorrow and not smooth when touched with a finger. Because the thermal conductivity of the organic gel film is extremely poor, the finger touch will have a warm feeling, and the inkless jade is not smooth, moist, and cool. a feeling of.

Refractive index: After measuring the refractive index of 10 coated emerald ring faces by means of a gem refractometer, it can be known that the refractive index of the coated jadeite is generally lower, far lower than the refractive index of natural jadeite. 1.52.

When using other conventional inspections such as specific gravity, fluorescence, color filter, dichroic mirror, ultraviolet fluorescence, etc., the difference between coated jade and natural jade is not obvious, and will not be described again.

IR

The infrared spectrum of this coated jadeite shows that there are two absorptions of 2343-1 and 2385cm-1 in the range of 2300-2400 cm-1, and 2856.1 cm-1, 2873.7 cm-1 and 2928.9 in the range of 2800-3000 cm-1. Four lines of cm-1 and 2958.7cm-1, of which 2873.7cm-1 and 2928.9cm-1 are v(-CH2 -) symmetric stretching vibration of epoxy resin and 2958.7cm-1 infrared first hand spectrum against symmetric stretching vibration The strength of the belt is relatively weak, indicating that the "film" of the coated jade is mainly epoxy.

Ultraviolet-visible absorption spectroscopy

The relationship between the UV-visible absorption spectrum of the coated jadeite and the natural jadeite is that both the green jadeite and the natural green jade have a strong absorption band of 630 nm and an absorption line of 437 nm, but the absorptive jadeite lacks the absorption band centered at 691 nm.

Laser Raman spectroscopy

Raman spectroscopy was carried out on different parts of the same covered jade ring. The test results showed that there was a Raman fingerprint peak of the jade in the part where the film fell off, and a Raman fingerprint of jade appeared in the part where the film did not fall off. The peak of the spectrum appears only at a width of 2000 cm-1.

Women Strapless Bra

Strapless Bra

Strapless Sports Bra,Strapless Bra,Strapless Backless Bra,Low Back Strapless Bra

Guangzhou Jiamanqi Apparel Co.,Ltd. , https://www.pretibisous.com