Author Topic: Rusts and red spots on gold  (Read 1991 times)

0 Members and 1 Guest are viewing this topic.

Offline flora79

  • Trade Count: (0)
  • Jr. Member
  • **
  • Posts: 175
  • Karma: 10
Rusts and red spots on gold
« on: January 16, 2013, 11:47:15 PM »

a collector bought a gold bar in 2010 and found red spots and rusts on it in 2012, what cause the oxidization?
http://en.shyzgw.com/New.asp?id=2076

Offline 1668Chris

  • Supporter
  • Trade Count: (+11)
  • Sr. Member
  • ****
  • Posts: 691
  • Karma: 34
    • Coin Armour
Re: Rusts and red spots on gold
« Reply #1 on: January 17, 2013, 06:33:00 AM »
This topic was discussed not to long ago on this thread:  http://china-mint.info/forum/index.php?topic=7783.0

The primary reason is due to impurities in the gold, mainly silver and copper.  These elements are concentrated during the process of making gold bars.  When silver and copper come into contact with harmful gases like chlorine and sulfur (which are found in the air in the form of pollution), they will oxidize and form spots.  While not very attractive, I doubt they will affect the intrinsic value of the bar.

Offline athenakelly

  • Trade Count: (0)
  • New
  • *
  • Posts: 1
  • Karma: 0
  • Gender: Female
Re: Rusts and red spots on gold
« Reply #2 on: February 07, 2013, 11:29:23 PM »
But is there any solution to avoid these spots? It looks bad specially in case of ornaments. Is there any proper care that is to be taken not to get red spots? Sometimes people feel that they are robbed by the vendors due to this.

Offline PCGS-ASIA

  • Trade Count: (0)
  • Jr. Member
  • **
  • Posts: 177
  • Karma: 15
    • PCGS-ASIA
Re: Rusts and red spots on gold
« Reply #3 on: February 08, 2013, 04:17:19 AM »
It is a fact of the alloy, as stated above.

If tiny lumps of impurities are near the surface, oxidation is guaranteed.
Sometimes, this can be addressed.  Sometimes not.