Conservation Showcase: Chinese 1994 10 Yuan Bi-metallic
Posted on 4/19/2011
A recent example from our conservation laboratory.
With increasing frequency, mints around the world are issuing coins in two distinct metals as both an anti-counterfeiting device and to increase interest among the numismatic community. Bi-metallic coins offer the numismatist greater visual interest and when it comes time for a professional conservator to remedy the effects of improper storage, special concerns.
This 1994 silver and gold bi-metallic Panda coin from China was recently submitted to NCS. Improper storage led to both a light haze to develop on the surface and, perhaps even more distractingly, a general speckled orange-red tone to arise. Dealing with two separate metals in one coin leads to special concerns when it comes to conserving a bi-metallic coin such as this Chinese piece. Both the hazing and red toning issues were remedied on this piece and the coin was able to grade with NGC at an optimum level because of the professional conservation work.
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