Expand the scope of knowledge,
1. The National Center for Quality Supervision and Inspection of Silicon Deep Processing Materials (hereinafter referred to as "National Inspection") is the first national inspection center in China approved by the General Administration of Quality Supervision, Inspection and Quarantine, which specializes in the quality inspection of silicon materials and its deep processing products. Located in Lianyungang, the bridgehead in the east of the New Eurasian Continental Bridge, the laboratory is located in Donghai County, the crystal capital of China and the silicon material industrial base of China, the timely center in the east.
2. The Center is a statutory inspection institution authorized by Jiangsu Bureau of Quality and Technical Supervision and recognized by China National Accreditation Committee for Conformity Assessment. To undertake the quality supervision, inspection and appraisal of gold, silver, diamonds, precious stones and other products, and provide users with quality inspection services for all kinds of gold and silver jewelry products (including precious metal jewelry such as gold, platinum, silver, diamonds, rubies, crystals, etc. 100 kinds of precious stones and jade products).
3. The station has an existing laboratory area of 350 square meters, equipped with professional quality inspectors for jewelry, and has a complete set of advanced gold, silver and jewelry detection equipment such as Nicolet 6700 Fourier transform infrared spectrometer, GIA microscope, diamond cutting proportioner, optical fiber spectrum, gem cathode luminescence instrument, diamond thermal conductivity instrument, desktop spectroscope and precious metal detector.
1. Look at the mark: gold ornaments sold in international or domestic regular stores are generally printed with the words of gold content, such as: 24K, 18K, 14K or 999 (99.9% gold, equivalent to 24K), 750, 583, etc. Generally speaking, it has such a mark.
2, weighing: real gold should feel heavy in your hand, fake gold feels lighter, because the density of gold is relatively high, about one and a half times that of silver, copper, lead, iron and other metals.
3. Listen to the sound: throw the gold on the hard ground and listen to the sound when it falls to the ground. The sound made by real gold is dull and heavy, usually clicking, and there is no lingering sound. The sound of fake gold is crisp and dull, usually sonorous, with a lingering sound. Besides, real gold does not jump more than three times when it hits the ground, and it is not as intense as fake gold.
4. Hardness test: If it is real gold, bending with handicrafts should feel softer, while fake gold feels harder.
5. Use fire: put the jewelry on the fire for barbecue. After the jewelry is slightly red, take it out and cool it. The color of pure gold jewelry is still as new, while the surface of K gold jewelry is a smoky gray oxide layer. The lower the color, the darker it is. After gold-plated jewelry is burned, the coating will disappear and its material will be exposed.
6. Use touchstone: select a black touchstone with delicate texture, mark it with gold test pieces with different (known) gold contents, then scrape the jewelry to be tested on the same touchstone, add concentrated nitric acid to remove impurities (metals other than gold), and compare it with the marked sample traces to mark the same chromaticity, which is the accurate gold content of the jewelry to be tested.
7, with a generation of device measurement:
(1) specific gravity method: This method uses the analytical balance as the measuring instrument, and calculates the specific gravity and color by Archimedes principle according to the different weights of ornaments in air and pure water. Specific gravity = weight in air/(weight in air minus weight in pure water).
(2)x-ray fluorescence spectrometry; This method uses a beam of X-rays (X-ray fluorescence spectrum generation) emitted by a precision instrument controlled by a computer to irradiate jewelry, and then the computer calculates the color and impurity element content of gold jewelry according to the recorded X-ray spectrum and intensity.