Set of 4: 29c Minerals Series 1992

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Minerals USA 29 Variscite ISHINGTON SEP 17 1992 20066 KOSL OW. DC INGTON SEP 17 1992 20066 Minerals USA 29 Wulfenite KOSL oW Minerals USA 29 Azurite ASTINGTON SEP 17 1992 20066 KOSL OW DC EARLY COPPER MINE RINGTO SEP 17 1992 20066 Minerais USA 29 Copper KOSLOW DC

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VARISCITE First Day of Issue: September 17, 1992 First Issue Location: Washington, D.C. Variscite is a phosphate mineral that occurs in glassy nodules, veins, or crusts in near-surface deposits. Formed by the action of phosphate waters on aluminous rocks, this mineral occurs in Germany, Austria, Czechoslova- kia, Zaire, Australia and Utah. It is also found on islands where phosphatic solutions from guano — seafowl ex- crement — have interacted with aluminous igneous rocks. Most gem quality variscite occurs in an extensive deposit at Fairfield, Utah. Commonly known at this location as Utahlite, it is found in nodular masses as much as a foot in diameter. Pale green in color, this semipre- cious gemstone is used extensively as an ornamental material in brooches, earrings and beads. Variscite is often substituted for turquoise, which it closely re- sembles, but is more porous and tends to absorb body oils which discolor it. Cut into sections, variscite frequently exhibits color variation near the center because of greater density, and may display "eyes” of other phosphate minerals as well. No. 92-115 First Day of Issue Postcard Collection ©1992 Fleetwood® Cheyenne, WY 82008-0001 Original painting for the First Day of Issue Postcard by Howard Koslow Fleetwood WULFENITE First Day of Issue: September 17, 1992 First Issue Location: Washington, D.C. The importance of minerals extends well beyond their usefulness as sources of metals. Minerals such as garnet and corundum are used as abrasives in modern industries throughout the world. Because of its high specific gravity and its ability to make “heavy mud," barite is used extensively by oil companies when drilling wells. Miner- als have aesthetic value as well and are one of nature's most exquisite art forms. Diamonds, rubies, emeralds and sapphires are but a few examples of nature's elegant minerals. Although not as well known, wulfenite is one of the most beautiful minerals in the world. Named in honor of Austrian mineralogist Franz Xaver von Wulfen, this stunning mineral has a resinous luster and occurs in various hues of yellow, orange, red and green. The red crystals from the Red Cloud Mine in Yuma County, Arizona are the most prized in the world. Wulfenite occurs in oxidized zones of lead and molybdenum de- posits. Very brittle and heavy, it has a hardness of about 3, and a specific gravity ranging from 6.7 to 7.0. No. 92-116 First Day of Issue Postcard Collection™ ©1992 Fleetwood® Cheyenne, WY 82008-0001 Original painting for the First Day of Issue Postcard by Howard Koslow Teetwood AZURITE First Day of Issue: September 17, 1992 First Issue Location: Washington, D.C. Azure in color, this beautiful mineral was used exten- sively as a blue pigment by European painters during the crystals of azurite have a remarkable luminous sheen, and are often used in fine pieces of jewelry. A common ore of copper, azurite is usually found near the surface of copper deposits, and almost always occurs with the more plentiful green-colored mineral malachite. Because of this, azurite is sometimes called blue malachite. Both azurite and malachite are frequently found in stalactite form, with one mineral wrapped around the other. When cut and polished in cross sections, these stalactites make beautiful ornamentations. Most of the ornamental speci- mens of this sort occur in Morenci, Arizona. Other areas where azurite is found include Bisbee, Arizona, Siberia and Chessy, France. The latter location has been famous for its azurite deposits for many years, and azurite is most often called chessylite in Europe and England. No. 92-117 First Day of Issue Postcard Collection ©1992 Fleetwood® Cheyenne, WY 82008-0001 Original painting for the First Day of Issue Postcard by Howard Koslow Heetwood COPPER First Day of Issue: September 17, 1992 First Issue Location: Washington, D.C. 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 role of transporting oxygen in the hemo- cyanin. Copper appears as a trace element in humans and acts as a catalyst in the formation of hemoglobin. No. 92-118 First Day of Issue Postcard Collection™ ©1992 Fleetwood® Cheyenne, WY 82008-0001 Original painting for the First Day of Issue Postcard by Howard Koslow Heetwood