1, National Jewelry Testing Center
Address: 526 1 Building 2 15, National Jewelry Testing Center, No.4 Beili South Road, Luohu District, Shenzhen.
2. Shenzhen Laboratory of National Jewelry and Jade Quality Supervision and Inspection Center
Address: 4B, Floor 4, Investment Building, No.4009 Shennan Avenue, Futian District, Shenzhen.
3. zhongwei Jewelry and Jade Quality Testing Center
Address: near No.8, Lane 1, Nan 'an New District, Baoan District, Shenzhen.
4. Guangdong Jewelry, Jade and Precious Metals Testing Center
Address: 5th Floor, Zone C, Building No.0/5, Shuibei Industrial Zone, Luohu District, Shenzhen.
Matters needing attention in gold detection
1, color discrimination:
Looking at the appearance color of gold, as the saying goes, gold is "seven green, eight yellow, nine purple and ten red", showing different colors due to different types and components of impurities. Pure gold is shiny and shiny, and mixed gold is a bit rough. 70% jewelry with gold is yellow with blue, 80% jewelry with gold is yellow, 90% jewelry with gold is yellow with purple, 100% jewelry with gold is red.
2. Weighing:
The specific gravity of gold is 19.3g/cm3, and the fineness is closely related to the specific gravity. When the specific gravity is close to 19.3, the content of pure gold is higher. Weigh it by hand to see if it is commensurate with its size. Large and light shapes may be adulterated. But generally, if you hold it in your hand, you can feel that it is real gold jewelry when you feel a little heavier, indicating that the gold body is small and heavy. Beware of silly light ornaments and carefully distinguish whether they are fakes or semi-fakes.
3, both soft and hard:
The higher the fineness of gold jewelry, the softer it is and the less elastic it is. Real gold will have faint traces when bitten by teeth or scraped by needles, and it will not break when folded by hand. The color is low and hard; The remixer is elastic, fragile and easily broken. Pure gold is soft and generally not used to make inlaid jewelry. Therefore, any so-called 24K inlaid gold jewelry must be fake.