Gold: gold
Chemical element: gold
Color: golden yellow
Melting point: 1064.43℃.
Specific gravity: 19.23
Hardness: 2.8
Chemical properties: stability, oxidation resistance and corrosion resistance.
It is malleable and very soft, and can be pressed into extremely thin gold foil. 1 g gold can be drawn into a thin gold thread 4 kilometers long. Gold is soft, can shape complex patterns, and is very malleable. Theoretically, 24K stands for pure gold. Pure gold, gold with a gold content of not less than 990%. Thousands of gold, gold with a gold content of not less than 999.
Gold medal maintenance:
(1) Do not mix and contact metals such as mercury, lead and tin to avoid discoloration;
Avoid contact with vegetable juices containing chemical elements, such as mustard juice, cauliflower juice, fish scales, etc.
(3) Don't store gold ornaments with sterling silver ornaments, so as not to collide and rub with each other and turn the surface of gold ornaments into silver.
(4) Gold ornaments are bright due to the addition of a "polishing" process in the processing, but after wearing for a long time, they gradually lose their brightness due to sweating and other factors. This is a normal phenomenon. In this case, the customer needs to return the jewelry to the jewelry store for cleaning.
⑤ Avoid putting K-gold jewelry together with other jewelry, especially diamonds, because different hardness will cause mutual friction and scratches, and store them separately in jewelry boxes.
Platinum knowledge
Platinum: platinum
Chemical element: platinum
Color: bright white with gray tone
Gloss: metallic luster
Melting point: 1773℃.
Specific gravity: 2 1.45
Hardness: 4-4.5
Chemical properties: stability, wear resistance, high temperature resistance and corrosion resistance.
Platinum is rarer than gold, with an annual mining capacity of only 5% of that of gold, and it can only be mined in a few places (mainly South Africa and Russia). In addition, processing platinum jewelry also requires a high level of technology, so platinum is the rarest and most precious among all kinds of precious metals.
The purity of platinum ornaments is generally 900‰, 950‰ and 990‰(Pt900, Pt950 and Pt990). Due to the high purity of platinum, it will not fade and change color, and it is durable. The pure white of platinum can well reflect the light of diamonds, and the high purity of platinum will not cause skin allergic reactions.
Platinum maintenance:
① Platinum is not easy to play a chemical role and has strong corrosion resistance, but all precious metals are relatively low in hardness, so it is easy to be scratched, and platinum is no exception. When wearing platinum jewelry, avoid contact with chemicals such as high hardness, bleach and detergent, and avoid wearing platinum jewelry when handling housework.
② Wash platinum jewelry with diluted soap solution, and then use a soft cloth to absorb water. Use non-abrasive cloth to remove fingerprints and stains on the surface, such as silver cloth or glasses cloth.
Palladium knowledge
Palladium: palladium
Chemical element: palladium
Color: silvery white
Gloss: metallic luster
Melting point: 1555℃.
Specific gravity: 12, lighter than platinum.
Hardness: 4-4.5, slightly harder than platinum.
Chemical properties: relatively stable, insoluble in organic acids, cold sulfuric acid or hydrochloric acid, and not easy to oxidize and lose luster under normal circumstances.
Palladium is one of the rarest precious metals in the world, and its content in the earth's crust is about one hundred millionth, which is much rarer than gold. Only a few countries in the world, such as Russia and South Africa, produce less than 5‰ gold every year. Rarer than platinum. Palladium is extremely tough, and jewelry made of palladium not only has the natural and charming luster like platinum, but also can withstand the tempering of years and last as long as new. Palladium has almost no impurities, high purity and white light. The purity of palladium is also very suitable for skin and will not cause skin allergies.
Palladium has excellent physical and chemical properties, high temperature resistance, corrosion resistance, wear resistance and strong ductility. It can replace platinum in purity, rarity and durability, and is the most ideal material for making jewelry or setting gems alone.
In the world, the moral imprint of palladium jewelry is "Pd" or "palladium", which is expressed by a few thousandths of purity. For example, the purity of Pd990 is 990‰, and the specifications of PD ornaments are PD 990, PD 950, PD 900 and PD 850.
Palladium maintenance:
Refer to the maintenance method of platinum.