Things that won't be written on the certificate, you know?
First, the certificate does not mark the optimized processing method.
In the identification of jewelry and jade, that is, whether it is natural or post-optimized, such as Nanhong and tourmaline, the identification certificate will not be marked with glue injection; Aquamarine and beeswax processed by heat treatment will not be marked on the certificate; There are also many colorful agates, the colors are particularly beautiful, and the certificate will not be marked with nature.
Two, the certificate does not indicate the origin and specific classification.
According to GB/T- 16552 Names of Jewelry and Jade and GB/T- 16553 Identification of Jewelry and Jade and Interpretation of National Standards for Jewelry and Jade.
1. According to GB/T- 16552, the names of places of origin such as Hetian jade, Manas jade and Qinghai jade are not used in these Detailed Rules. In the identification of specific jade products, the origin is very uncertain, so the origin is not distinguished, for example, the name of "Hetian sapphire" is not written. This rule is also in line with international practice: international beads
2. Item (b) of Article 1 of the practical rules of CIBJO Gem Manual of Jewelry Federation: the place of origin should not be indicated in commercial documents; Item (3) of the second experimental appraisal report: the place of origin of the gem does not need to be indicated.
According to the traditional viewpoint and industry practice, the varieties of hetian jade in this rule are classified according to their color characteristics. Considering the complexity of jade products, the commercial appraisal certificate should adopt the principle of "grading without grading" The preliminary evaluation of quality adopts a simple and comprehensive description of color and texture.
The certificate will not indicate the origin of the product, and the origin directly determines the value of the product. For example, Hetian jade will not indicate Xinjiang material, Qinghai material and Russian material; The appraisal standard of Hetian jade is that the density and refractive index reach the standard before the appraisal certificate can be issued. # Hotan Jade #
Is it the same south red tile or nine mouths? It's not on the certificate, is it Are they all written by Nan Hong?
Third, the certificate does not indicate the old and new materials.
There is a difference between old jadeite and tender jadeite. The old jadeite is dense, stable in texture and structure, and does not change color for a long time. On the contrary, the tender jade is loose and will change over time, but it is indeed jade, and the appraisal certificate is also A goods.
Former old playmates should know that you can't get the original mine certificate by playing with your hands. Now anyone who has soaked in oil is fine, and you can get the original ore certificate completely.
The black sapphire in Guangxi was first discovered at the end of 20 12. At first, the hornblende content of Guangxi black sapphire was so high that it could not be certified as Hetian jade. Therefore, the national standard specially revised the identification standard of Hetian jade, and directly included black sapphire in the category of Hetian jade. Later, for a long time, Guangxi black and green was called "Hetian Jade Tower Green"