Conservation Showcase: 1904 $20 Double Eagle
Posted on 11/10/2009
|Click to enlarge||Click to enlarge|
When a gold coin is received for conservation, the most frequent problem is the development of unsightly reddish spots on the surface. These spots are commonly known as copper spots and are caused by an improper blend in the alloy of the coin. Over time these areas of higher copper or silver concentration will lead to this common spotting phenomenon on the surface. This particular 1904 $20 had developed several large spots on Liberty’s forehead and in the field.
Conserving these kinds of gold coins can be tricky. A coin’s original look or skin is so important to the grading of these coins that extreme steps must be taken to remove evidence of the spot yet leave the rest of the coin. The conservators at NCS were able to clear up the copper spots from this particular coin allowing it to grade with NGC numerically following the conservation efforts.