Jadeite jewelry will be divided among five categories according to its quality, the Yunnan Research Institute of Gem & Jade Quality Supervision and Inspection said on Monday.

The five categories are excellent, very good, good, common and bad.

Kunming Eastshow Jade Jewelry Co Ltd has signed an agreement with the institute saying the company's airport shops must provide consumers with certificates vouching for the authenticity and grading the quality of pieces of jadeite jewelry costing more than 3,000 yuan ($470).

In the meantime, the authenticity of jadeite jewelry costing less than 3,000 yuan must also be certified.

Chen Jianfei, chairman of the Kunming Eastshow Jade Jewelry Company, said, "Assessing the quality of jadeite jewelry will be helpful in establishing standards for marketing practices in the jade industry, pushing the industry toward internationalization and paving the way for domestic jadeite companies to enter the international market."

Yunnan Research Institute of Gem & Jade Quality Supervision and Inspection put forward the idea of conducting formal assessments of the quality of jade jewelry and drew up inspection standards for the jewelry in 2009. Contemporary techniques used to assess the quality of jadeite jewelry can meet market demands for quality assurance.

The local standard employed to grade the quality of jadeite jewelry has been approved by the China National Accreditation Service for Conformity Assessment and has been listed in the service's inspection approval directory.

The jade, decoration stone and building stone industries are pillars of Yunnan province's economy. Statistics show the industries produced 40 billion yuan worth of materials last year. The total value of the stone industry is expected to reach 97 billion yuan in 2015.