Copper Maximum Cards Geology, Rocks & Minerals


Stock #: 235611
Type: Postcard
Era: Continental Chrome
Publisher: Fleetwood
Postmark: 1992 Sep-17
PM City: Washington
PM State: DC
Stamp: 29c
Philatelic Notes: First Day
Size: 4" x 5.75" (10.25 x 15 cm)
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First Day of Issue: September 17, 1992 First Issue Location: Washington, DC Although copper is found adhered to other minerals such as malachite, bornite and cuprite, it is the only metal that commonly occurs in a free metallic state -- a native form. Copper in this pure form was first used by Neolithic man as a substitute for stone. Copper's malleability allows it to easily be shaped into wire and, with the exception of silver, it conducts electricity and heat better than any other metal. Hence, the majority of copper produced in the world is used for electrical purposes. The greatest deposit of copper ore in the United States is found in northern Michigan. Here, along Lake Superior's Keeweenaw Peninsula, a four-mile-wide belt of native copper extends for 100 miles. This abundant metal is also found in the body chemistry of mollusks, arthropods and humans. In blue-blooded mollusks and crustaceans, it plays the vital rold of transporting oxygen in the hemocyanin. Copper appears as a trace element in humans and acts as a catalyst in the formation of hemoglobin