Platinum, also known as platinum, code name PT. Its color is silvery white, which is a white precious metal. The hardness is 4-4.5, the relative density is 2 1.45g/cm3, and the melting point is as high as 1773 degrees Celsius. Because of its ductility, it can be drawn into filaments and rolled into thin foil. Platinum is chemically stable, insoluble in strong acid and alkali, and not easy to chlorinate, so it is widely used in chemical industry and jewelry industry. The elements similar to platinum are palladium, rhodium and iridium, which are called platinum group elements, and there are extensive isomorphic substitutions among them.
Pure platinum is platinum with high purity. Theoretically, the purity should reach 100%, but in fact, gold is barefoot, platinum is less than platinum, and the purity of pure platinum is always lower than 100%.
Pure platinum is soft in texture, so the strength of platinum jewelry is limited. Generally, pure platinum jewelry without precious stones is made, and the styles include various car flower rings, necklaces, earrings, brooches and so on.
The hardness of pure platinum is not enough when it is inlaid with gems, so a small amount of metals such as iridium, palladium, cobalt and copper should be added to improve its hardness and toughness. Therefore, the platinum products we usually see, like gold products, exist in the form of alloys.
In foreign countries, Platinum jewelry is engraved with the words PT or PLAT or Platinum and the thousandth digit indicating purity. For example, platinum marked with 900PT indicates a purity of 90%.
Platinum and silver are similar in color, and inexperienced people are easily confused.
There are five ways to distinguish platinum from silver, as follows:
Comparative method. Platinum is grayish white to the naked eye, with a hard texture and a hardness of 4.3. With naked eyes, the color of silver is white, the texture is fine and smooth, the hardness is lower than that of platinum, and the hardness is 2.7.
Identification seal. Because every piece of jewelry must be engraved with a component seal, as long as it is Pt, platinum or Plat, it is platinum; If you see S or silver, it's silver. Also note that the symbol for copper and silver plating is SF.
Weigh. This method can be used if the seal is blurred or has been cut off. The density of platinum is very high, the specific gravity is 2 1.4kg/m3, and the specific gravity of silver is 10.49kg/m3. In this way, the weight of the same volume of silver is only half that of platinum, so it is easy to distinguish the two.
Cremation identification. Sometimes the material is less, the weight on the hand is not obvious, and there is no seal at the same time, so this method has to be adopted. After platinum is heated or burned and cooled, its color remains unchanged; When silver is heated or burned and cooled, its color becomes moist red or black red.
Chemical methods. Grind platinum on the touchstone and drop a few drops of mixed solution of nitric acid and hydrochloric acid. If there are grinding marks, it means platinum. As for the fineness, there are only some differences in color. If this liquid is dropped on silverware, the traces of wear will dissolve.
Platinum and K gold can be distinguished from the following points:
1. Platinum is a natural pure white metal, and K platinum is an alloy of gold with palladium, nickel, silver and zinc, so it is also called K platinum.
2. Platinum is relatively rare, and its annual output is much less than that of gold, which is more precious.
3. The density of platinum is very high. A piece of platinum jewelry is 20% heavier than a similar piece of K-gold jewelry.
4. Platinum is resistant to corrosion and oxidation by strong acid and alkali, and its chemical properties are more stable than that of K platinum.
5. Platinum ornaments are marked with "PT" logo and color. For example, "PT900" refers to the platinum products of this jewelry, and the platinum content is 90%.
In foreign countries, Platinum jewelry is engraved with the words PT or PLAT or Platinum and the thousandth digit indicating purity. For example, platinum marked with 900PT indicates a purity of 90%.
According to international principles and China's actual situation, China stipulates that platinum products must be engraved with the percentage of platinum and the words platinum. According to the different purity, the common varieties are PT990, PT900 and PT850, indicating that the platinum content is 99%, 90% and 85% respectively.
golden
Gold is a precious metal with high value and content. Praise words such as "resplendent", "real gold is not afraid of fire" and "the book has its own gold house" all express the lofty position of gold in people's hearts. In order to participate in future gold investment and gain opportunities for investment appreciation and preservation in the gold market, it is necessary to understand the attributes, characteristics and functions of gold in monetary finance.
As a precious metal, gold has good physical properties, such as high melting point, reaching l064.43 degrees Celsius. "Real gold is not afraid of fire" means that gold is not easy to melt under the general flame. The density is19.31g/cm3 (at18℃), so it feels heavy. Good toughness and ductility, good electrical conductivity. Pure gold is bright yellow, but the color changes greatly after mixing with other metals, such as gold-copper alloy is dark red, and silver-containing alloy is light yellow or grayish white. Gold is easily ground into powder, which is also the reason why gold is dispersed in nature. Pure gold jewelry is also easy to wear and lose weight.