How to identify Pt990 and silver jewelry

How to identify Pt990 and silver jewelry ? Pt990 platinum color and most rich in exquisite extended features , making it a major jewelry supplier making materials . Expensive and rare , never fade oxidation stability is the nature of its characteristics . As with Pt990 platinum silver color is very close , it is easy to see from the appearance of confusion , here are some simple distinction between the two approaches:

 

One, identified Chop: jewelry products according to national standards , should be marked with its purity seal mark . Such as jewelry on the "PT" or "PLATNUM" or "PLAT" word , it is platinum, such as jewelry on the "S" or "SILVER" word , it is silver.

 

Second, weigh : Pt990 platinum accounted for 21.4 , the proportion of silver is 10.49 , the same volume of silver platinum heavier than double the normal hand weigh weight to distinguish between the two .jewelry factory

 

Third, the appearance and hardness comparison: Platinum will be slightly careful observation with the naked eye bright white with gray , hard, difficult to characterize with a pin scars , its Mohs hardness of 4.3 , while the silver white color, smooth texture and delicate , a light gray or black oxide will become black . Its Mohs hardness of 2.7 , much softer than platinum .

 

Fourth, the fire method : Platinum resistant to high temperature oxidation, its melting point up to 1770 degrees Celsius, with the general high temperature ( petrol ) fire does not melt , after cooling , the color unchanged or with quenching traces. The low melting point of silver , after the fire at high temperature , depending on the amount of silver , and its color was red, black and red or black black.

 

Fifth, the chemical method : Platinum extremely stable chemical properties , corrosion resistance , the case of most of the acid ( aqua regia , magic acid addition ) , alkaline solutions were not react , while silver corrosion resistant to acid , hydrochloric acid into the surface becomes gray powdery substance , nitric acid will dissolve into the evolution of gas NOx, into sulfuric acid black surface .jewelry manufacturer