Wulfenite
By Bob Farrar
by Bob Farrar
The Mineral of the Month for October is wulfenite. Named for the Austria-Hungarian mineralogist Xavier Wulfen, wulfenite is one of the most popular minerals among collectors, due in large part to its often-well-formed crystals
that occur in a range of beautiful colors. Wulfenite consists of lead molybdate, PbMoO4. It crystallizes in the tetragonal system. Crystals of wulfenite are frequently very distinctive. Usually, the crystals are square wafers that are often very thin and delicate. Sometimes, however, the faces that form the flat sides are produced into a pyramidal shape. In these cases, the top of the pyramid may be flat, or it may continue to a point, forming a bipyramidal crystal. Colors in wulfenite are often very brilliant, and can range from almost white to gray, brown, yellow, orange, and red. The crystals have a high adamantine (diamond-like) luster. Other physical properties include a hardness of 2.7 to 3.0, a specific gravity of 6.8, and a pyramidal cleavage. Crystal form and color are usually sufficient to distinguish wulfenite from other minerals. Wulfenite typically occurs in deeply weathered zones of lead deposits in the presence of molybdenum, and is usually best developed in arid climates. The best-known localities are in the American Southwest. Among the most famous of these is the Red Cloud Mine, La Paz Co., Arizona, which has produced bright reddish-orange crystals up to 5 cm across. Another Arizona locality that has long been known for wulfenite is the Rowley Mine, Maricopa Co. Additional localities in Arizona include the Mammoth Mine, Old Yuma Mine, Defiance Mine, and others too numerous tomention. California, by contrast, has produced only one significant find of wulfenite, that being in 1972 at the Darwin Mine by prominent minerologist Wolfgang Mueller. In Mexico, Los Lamentos is known for crystals that are blockier in form than the usual wulfenites. Good wulfenites also come from the Ojuela Mine in Durango, and other Mexican localities.Worldwide localities are many. The type locality is Bleiberg, Austria, where yellow-orange crystals occur. Wulfenite has also been found at a number of other European sites. Wulfenite occurs at several localities in Morocco, including Touissit and Mibladen. It was among the many fine minerals found at Tsumeb, Namibia. In recent years China has been producing wulfenite. Other countries where wulfenite is found include Iran, Kazakhstan, and Australia. While wulfenite is more common in arid climates like Arizona, it can occur in wetter climates as well. There are, in fact, several localities in the eastern United States. For example, it occurs in a lead mine in Loudville, Massachusetts. Wulfenite has also been found with pyromorphite at Phoenixville, Pennsylvania. Wulfenite has even been found in Maryland; micro crystals have been found at Union Bridge in Carroll County. Good wulfenite specimens can fetch high prices on the mineral market. However, there are enough more modest specimens around that most any collector can add this beautiful mineral to their collection.
The Mineral of the Month for October is wulfenite. Named for the Austria-Hungarian mineralogist Xavier Wulfen, wulfenite is one of the most popular minerals among collectors, due in large part to its often-well-formed crystals
that occur in a range of beautiful colors. Wulfenite consists of lead molybdate, PbMoO4. It crystallizes in the tetragonal system. Crystals of wulfenite are frequently very distinctive. Usually, the crystals are square wafers that are often very thin and delicate. Sometimes, however, the faces that form the flat sides are produced into a pyramidal shape. In these cases, the top of the pyramid may be flat, or it may continue to a point, forming a bipyramidal crystal. Colors in wulfenite are often very brilliant, and can range from almost white to gray, brown, yellow, orange, and red. The crystals have a high adamantine (diamond-like) luster. Other physical properties include a hardness of 2.7 to 3.0, a specific gravity of 6.8, and a pyramidal cleavage. Crystal form and color are usually sufficient to distinguish wulfenite from other minerals. Wulfenite typically occurs in deeply weathered zones of lead deposits in the presence of molybdenum, and is usually best developed in arid climates. The best-known localities are in the American Southwest. Among the most famous of these is the Red Cloud Mine, La Paz Co., Arizona, which has produced bright reddish-orange crystals up to 5 cm across. Another Arizona locality that has long been known for wulfenite is the Rowley Mine, Maricopa Co. Additional localities in Arizona include the Mammoth Mine, Old Yuma Mine, Defiance Mine, and others too numerous tomention. California, by contrast, has produced only one significant find of wulfenite, that being in 1972 at the Darwin Mine by prominent minerologist Wolfgang Mueller. In Mexico, Los Lamentos is known for crystals that are blockier in form than the usual wulfenites. Good wulfenites also come from the Ojuela Mine in Durango, and other Mexican localities.Worldwide localities are many. The type locality is Bleiberg, Austria, where yellow-orange crystals occur. Wulfenite has also been found at a number of other European sites. Wulfenite occurs at several localities in Morocco, including Touissit and Mibladen. It was among the many fine minerals found at Tsumeb, Namibia. In recent years China has been producing wulfenite. Other countries where wulfenite is found include Iran, Kazakhstan, and Australia. While wulfenite is more common in arid climates like Arizona, it can occur in wetter climates as well. There are, in fact, several localities in the eastern United States. For example, it occurs in a lead mine in Loudville, Massachusetts. Wulfenite has also been found with pyromorphite at Phoenixville, Pennsylvania. Wulfenite has even been found in Maryland; micro crystals have been found at Union Bridge in Carroll County. Good wulfenite specimens can fetch high prices on the mineral market. However, there are enough more modest specimens around that most any collector can add this beautiful mineral to their collection.
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