Platinum and similar metals to identify

Platinum with white and silver Freshwater pearls streak, hardness 4-4.5, the relative density of 21.45, the chemical nature of stable, insoluble in common acids for identification of features, easy to do Cultured pearls with their similar metal.
Platinum metals lead and aluminum, compared with a Akoya pearls higher hardness, the relative deformation is not easy. The latter two because of inelastic deformation can not be restored; and the relative density of platinum than the small, lead to 11.36, aluminum and 2.7, respectively, platinum is about 1 / 2 and 1 / 8, just hand Jom test weight will be Pearl jewelry able to tell.
Platinum gold and silver to the size of the relative density, hardness level, the chemical nature of the difference between the stability of the. Although silver is silver-white, but the relative density of 10.53, only platinum 1 / 2; and low hardness, inflexibility, it is zoned light can also be left with the nail marks on foil sheet can be easily changed hands folded, and difficult to recover; coupled with instability in the chemical properties of silver, the event will be dissolved in nitric acid and the release of nitrogen dioxide gas. The Platinum does not dissolve in nitric acid, in the heated water can be quickly dissolved Wang, at room temperature, its very slow dissolution rate is generally difficult to detect visually.
Platinum is a very good catalyst for the use of this feature to quickly identify platinum. Commonly used hydrogen peroxide reaction, the specific method is: Take a few analytes powder, placed Sheng hydrogen peroxide (H2O2) plastic bottle, if platinum is to immediately roll bubble hydrogen peroxide, decomposition large amounts of oxygen, the reaction was still intact after the platinum not move one, but also recovery (only played the role of accelerating decomposition); if the other white Tahitian pearls metals such as silver, lead, aluminum does not have this reaction.