Types of jade articles:
1, A-type jade refers to natural jade that has not changed its original quality except hand carving, which is often said to be genuine, and is generally appraised by the National Jewelry Appraisal Center.
2. Class B goods refer to some inferior jade with a lot of impurities, which are removed by pickling and then injected with transparent liquid to make it more crystal clear and beautiful.
3. Class C goods are fake jade made by pickling inferior jade to remove impurities and dyeing it.
Experts said: "because the internal structure of the latter two has been changed, there is a gap of dozens of times in value with A-grade jade. At present, there is a widespread practice in the market to pretend to be natural jade with B and C commodities. "
Extended data:
The whole pickling process of jadeite B:
1, material selection.
Generally, jadeite wool with coarse particles, poor water head, loose structure and low price is selected. The reason is that these natural jadeite seeds with green stripes and patches have deposited many traces of unclean brown and grayish yellow iron between mineral particles in jadeite during long-term transportation in rivers, which has affected the beauty of jadeite. The purpose of optimization is to remove dirty color and increase the range of green.
2. Preliminary treatment.
The jadeite rough is cut into semi-finished jadeite products and reinforced with iron wire.
3. Acid leaching and cleaning.
Soak jadeite in hydrochloric acid 1 ~ 2 weeks. After iron is dissolved in acid, the background color of jadeite will be bleached. When the acid dissolves, the edges of some minerals will also be dissolved, and the mosaic structure between minerals will be destroyed.
In this way, hydrochloric acid dissolves fine mineral particles and impurities in jadeite, so that microcracks in jadeite are opened, and then washed with clear water.
4. Glue injection.
In order to consolidate the original structure, acid-soluble jadeite was put into a high-pressure machine, and liquid epoxy resin or inorganic filler was pressed into microcracks. This colorless and transparent filler replaces brown iron, makes up for the amplified microcracks between minerals, and improves the transparency of jadeite.
At the same time, the original green stripes of jadeite are reflected in the transparent filler, which expands the original green area. In this way, after artificial bleaching, the injected jadeite is clean, bright green and transparent under the reflected light.
5. Grinding and polishing.
The jadeite injected with glue is polished after the glue is solidified, and then made into jadeite B goods.
Baidu Encyclopedia-Jade Identification?