PT is the abbreviation of platinum, also called pure white gold, positive platinum or true platinum. Pure platinum is relatively soft, and the addition of metals such as ruthenium, rhodium and palladium will increase its hardness.

(1) Pt900, with a platinum content of not less than 900‰, can be identified as Pt900 or Pt 900.

②Pt950, which requires that the platinum content should not be less than 950‰, can be identified as Pt950 or Pt950.

(3) Pt990, which requires that the platinum content should not be less than 990‰, can be identified as Pt990 or Pt 990, which is sufficient platinum. Occasionally, we can see Pt850 (platinum content should not be less than 85.0‰) and Pt750 (platinum content should not be less than 75.0‰).

PD stands for palladium, and gold is a member of the platinum group. It is silvery white, lighter than platinum and slightly harder than platinum. In terms of price, palladium is much cheaper than platinum; In terms of texture, palladium is light and brittle, while palladium jewelry is easy to fade, deform and wear after being used for a period of time because of its strong chemical properties of absorbing gas. Based on the above characteristics, the color of palladium jewelry will darken after wearing for a period of time.

At present, the most popular palladium ornaments on the market are Pd950 and Pd990, and the ring holder will be marked with corresponding marks:

①Pd950, which requires that the content of palladium should not be less than 950‰, can be identified as Pd950 or Pd950.

②Pd990, which requires that the content of palladium should not be less than 990‰, can be identified as Pd990 or Pd990. Palladium jewelry with a palladium content of not less than 750‰ and 500‰ is mainly used for inlaying. It is not allowed to call palladium ornaments "palladium platinum ornaments" or "palladium platinum ornaments" and other ambiguous names. In addition, the standard also requires that the weight of precious metal jewelry should be kept to two decimal places, and the negative deviation of the weight of a single jewelry with a weight less than 100 g should not be greater than 0.0 1 g.

As for PC, it's a brand.