How is jade identification and testing conducted? major!

The authenticity of jade is always the most troublesome problem. Although it is possible to make a simple identification based on some obvious characteristics of the jade surface, such as gloss and jade texture , if you want to get more accurate and reassuring results, you still have to go to a professional organization for identification and testing.

So how do professional organizations conduct jade testing?

Let’s take a look at an appraisal case from the testing room of Guangdong Jewelry, Jade and Precious Metals Testing Center (GTC) .

Figure 1 Sample appearance

The sample being tested was a jadeite ring, see Figure 1 above.

After various tests, the results are as follows;

Conventional test: Observed with naked eyes, it is green with glassy luster. The mineral particles are coarse and have a columnar structure.

Refractive index test: 1.66 (spot test), but the boundary between light and dark is fuzzy. Different testers reported a test value of 1.62.

Spectroscopic observation: Cr spectrum and 437nm absorption.

Infrared spectrum test: original object mirror reflection method, after comparing with the reference spectrum, some abnormalities were found, the spectrum is shown in Figure 2.

Figure 2 Comparison of infrared spectra of original mirror reflection

Due to multiple anomalies, the inspector decided to remove the ring face for further testing.

Tested using the hydrostatic weighing method, the specific gravity was 3.25, which meets the identification characteristics of jadeite.

The refractive index was carefully tested again and again, and the measured value was 1.66 (point measurement), but bright spots appeared in the dark areas. When the view was moved to the 1.62 scale, the spots disappeared, as shown in Figure 3.

Figure 3 Schematic diagram of refractive index test

From this, it can be determined that there are two minerals with significantly different refractive indices in the sample , one with a refractive index of 1.66 and the other with a refractive index of 1.62.

Magnified observation under a microscope: columnar granular structure, the mineral particles are curved, see Figure 4. When observing the surface using reflected light, obvious gloss differences can be seen, see Figure 5.

Figure 4 The original object under a 30x gem microscope with orthogonal polarization

Figure 5 Observation with reflected light under a 30x microscope

In summary, the tester believes that in addition to jadeite, there is another type of mineral in this sample, which is speculated to be the main mineral of the amphibole family based on the refractive index , but further confirmation is needed. As to whether the sample can be called "jade" is a question worth pondering. The entire testing process can be said to be very serious and rigorous.

Finally, let’s take a look at what the appraisal certificate issued by the testing center looks like. Remember it.

Guangdong Province Gemstone and Precious Metals Testing Center Appraisal Certificate

Domestic jewelry appraisal institutions are currently divided into five categories: national, provincial, regional, college, and association (or market) levels . Provincial levels are affiliated with the Provincial Geological Bureau/Ministry of Land and Resources, or are provincial jewelry appraisal authority institutions that have been certified by the Provincial Quality and Technical Supervision Bureau. The Guangdong Jewelry, Jade and Precious Metals Testing Center (GTC) is a provincial appraisal institution.

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