1, look at the mark. If the jewelry has "Pt" or printed "Platnum" or "Plat" words, it is white gold; such as "S "or" Silver "word, is silver.
2, weighing method. Platinum iron specific gravity is 21.4, the specific gravity of silver is 10.49. the same volume of material weight comparison, the weight of white gold is almost double the weight of silver.
3, appearance comparison method. Platinum is gray-white, the texture is relatively hard; and silver is white , the texture is delicate and smooth, softer than white gold.
4, fire method. After high-temperature burning and cooling, the color of white gold is unchanged, still grayish-white; and silver is changed to run red, or black red.
5, chemical identification method. Grind white gold on the touchstone, with nitric acid and hydrochloric acid drops on the touchstone, if the material exists, is white gold; will be ground on the touchstone, a few drops of nitric acid, and rinse with water, if the material disappears, is silver.
Extended Information
Applications
Of the 245 tons of platinum sold in 2010, 113 tons (46%) were used in automotive catalytic converters, 76 tons (31%) were used in jewelry, and the remaining 35.5 tons were used in applications that included investments, electrodes, anticancer medicines, oxygen sensors, spark plugs and turbo engines.
Catalysts
Platinum's greatest use is as a catalyst for chemical reactions, which are usually platinum black.In the early 1800s, chemists began using platinum powder to catalyze the reaction of hydrogen ignition. Platinum's largest current application is in catalytic converters for automobiles, enabling the complete combustion of low concentrations of unburned hydrocarbons in exhaust gases to produce carbon dioxide and water vapor. In the petroleum industry, platinum can be used to catalyze a number of different reactions, notably the catalytic reforming of naphtha into higher octane gasoline. Platinum dioxide (or Adams' catalyst) is a catalyst for hydrogenation reactions, especially for the production of vegetable oils. Platinum metal catalyzes the decomposition of hydrogen peroxide into water and oxygen very well.
Standards of Weights and Measures
Between 1889 and 1960, the meter was defined by the length of a special platinum-iridium alloy (90 to 10) rod called the International Metric System (IMS), while the 1799 IMS was made of platinum. The International Kilogram Original is a cylinder made of the same platinum-iridium alloy from 1879, and is still the standard weight for the kilogram.
Standard hydrogen electrodes are made of platinum, again because of the high corrosion resistance of platinum.
Precious metals
Platinum is a precious metal trade commodity. The ISO currency code for platinum ingots is "XPT". Platinum coins, bars and ingots can be traded or collected. Since platinum is not easily eroded and has a shiny appearance, it is also used as jewelry, usually in 90% to 95% alloys. Publications on trading jewelry generally recommend that jewelers scratch the surface of the platinum.
In the watchmaking industry, a number of companies use platinum for limited edition watch collections. Platinum doesn't lose its luster and doesn't scratch (compared to gold), making it an ideal material for watches.
Like other industrially traded commodities, platinum is more volatile than gold, and in 2008 it fell from $2,252 to $774 per troy ounce, a drop of nearly two-thirds in market value. This compares with a fall in the price of gold from around $1,000 to around $700 an ounce over the same period, a fall of just one-third in market value.
In an economy of sustained and steady growth, the platinum price tends to double the gold price, while during periods of instability, the platinum price generally falls below the level of the gold price due to lower industrial demand. During economic stagnation, the price of gold is more stable because its demand is not driven by industrial use. in the 18th century, Louis XV of France, in view of the rarity of platinum, proclaimed it to be the only metal worthy of a king.
Other uses
In the laboratory, platinum wires are used as electrodes. Thermogravimetric analysis uses platinum disks and holders because it must be kept strictly chemically inert at high temperatures (about 1000°C). Platinum is used as an alloying additive in a variety of metallic devices such as wire, corrosion-resistant laboratory vessels, medical devices, dentures, electrical contacts and thermocouples. Platinum-cobalt alloys and iron-platinum alloys can be made into powerful permanent magnets. They are also the main material for the record layer in hard disk discs. Platinum-containing anodes are used in ships, pipelines and steel docks.
Symbol of honor
Platinum is extremely rare and is often considered a symbol of honor. Platinum levels of service are generally higher for credit cards, charge cards, and certain membership cards than for gold cards. For records, "platinum" is the second highest honor, below diamond and above gold, silver and bronze. In the U.S., for example, a record that sells more than one million copies is called a "platinum record," while a record that sells more than ten million copies is called a "diamond record. Other items are called "platinum" if they have a silvery-white surface. The Queen Elizabeth Crown was made for the coronation of George VI, and its frame is made of platinum. It was the first English crown to use platinum.
Reference: Baidu Encyclopedia - Platinum