NGTC is GIA's only partner in Chinese mainland, so its diamond color classification is similar to GIA's. According to the international diamond color classification table, it is represented by the English letter D-N, and * * * is divided into 12 grade. According to the color from light to deep, it is divided into seven categories, namely extremely white, excellent white, white, yellow white, yellow white, light yellow and yellow.

The specific grade division is more detailed, and the color of D-E grade is extremely white; F-G color is excellent white; Class h color is white; I-J grade color is yellow and white; K-L colors are light yellow and white; M-N color is light yellow; N-class color is yellow. Close to grade E is pure and colorless, extremely transparent, without any impurities, and the closer to grade N, the darker the color.

Extended data:

NGTC takes employees in jewelry industry, students majoring in jewelry, amateurs, people who are about to engage in jewelry industry and consumers as training targets. The training course covers jewelry management, management, sales, planning, identification, design and processing.

According to the characteristics of jewelry industry, NGTC adopts regular and irregular training methods, combining face-to-face teaching and correspondence to provide training services for the industry. The curriculum arrangement emphasizes the close combination of theory and practice, and pays attention to cultivating students' practical operation and actual combat coping ability, so as to apply what they have learned. In addition, NGTC also provides one-on-one training services for jewelry enterprises, and carries out special training according to the characteristics, problems and needs of enterprises.

NGTC has domestic first-class teaching environment and experimental equipment, rich teaching specimens at home and abroad, and a group of professional vocational education teachers, and employs authoritative experts and scholars at home and abroad to participate in teaching activities. Now it has gradually formed an education and training network with Beijing as the center and radiating the whole country.

Baidu Encyclopedia-Diamond Certificate

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