Table of Contents

6. Metals and Surfaces

6.2 Do Gold Coins Also Tarnish?

Explanation of the Question 

Gold is considered one of the most durable precious metals and is often associated with a permanently unchanged surface. It is therefore all the more surprising when discoloration nevertheless appears on a gold coin. Many collectors therefore wonder whether gold can tarnish and what causes such changes.

 

Answer

In general usage, visible discoloration on precious metals is often referred to as “tarnishing.” In this sense, based on our experience, the question can generally be answered in the affirmative. We have found that gold coins can also exhibit visible surface changes.

Pure gold, however, is significantly less reactive than silver and under normal environmental conditions rarely shows visible surface changes. Depending on the issue, gold coins are made of fine gold or gold alloys. External influences or residues on the surface can cause more or less pronounced visible changes. In alloyed gold coins, the added metals, such as silver or copper, can contribute to surface changes under certain conditions. Alloys containing copper, such as rose gold, are particularly prone to visible surface changes. This is partly because copper is significantly more reactive than gold.

In this context, the phenomenon of “Red Spots” or “Rotflecken” is also frequently mentioned. These are reddish or brownish spots on the surface of gold coins. Possible causes include local contamination, particularly contamination with copper. However, the exact cause can vary from case to case.

Discoloration on a gold coin is not necessarily an indication of poor quality or a counterfeit.

 

Explanation

Gold is one of the most chemically stable precious metals. In general, the higher the fine-gold content of a coin, the lower its tendency to undergo chemical surface changes.

Even coins made of fine gold can, in rare cases, show visible changes. Possible causes include residues from manufacturing or packaging, fingerprints, unsuitable storage conditions, or other environmental influences. Not every discoloration can therefore be attributed to the gold itself.

Depending on the cause, the changes may appear differently, for example as discoloration, spots, or matte areas. For a reliable assessment, the material, manufacturing process, storage conditions, and type of discoloration should be considered together.

 

Although gold is significantly more durable than silver, the occurrence of individual surface changes cannot always be completely ruled out. Gold coins should also be handled only with clean hands or suitable gloves whenever possible and stored in an appropriate storage system. A dry, clean, and as stable as possible storage environment helps to reduce surface changes.

If discoloration occurs, premature attempts at cleaning should be avoided. Improper cleaning measures can permanently alter the original surface and impair the collector value more severely than the discoloration itself.

This article is part of the Satoshi Silver Academy – a knowledge platform covering modern coins, medals, blockchain technology, and high-quality collectible objects.