Page 39 - visitorGuide

into Oklahoma and Kansas. This area is famous for pink dolomite crystals
like these.
Gift from the Geology Museum, Colorado School of Mines, Golden, Colorado.

■ Goethite
Goethite is a natural rust that commonly forms when iron-bearing rocks and
minerals are exposed to water and oxygen. It is named for Johann Wolfgang
von Goethe (1749–1832), a German philosopher and poet who was also an
amateur mineralogist.

■ Gem Coral
This pink, gem-quality coral was dredged
from the western outer slope of Bikini
Atoll at a depth of about 46 m (150 ft), dur-
ing the Bikini Scientific Re-Survey in the
summer of 1947.
Collected and donated by R. Dana Russell, Estes
Park, Colorado.

Native Copper ■ Scalenohedral Calcite Twin
Calcite is a common mineral in the
ores of the tri-state mining district of
Missouri, Oklahoma, and Kansas, as men-
tioned above.The district is known for the
golden yellow scalenohedral crystals, some
more than a meter (3 ft) long.

Collected by Charles J. Adami in 1899. Gift from the Geology Museum, Colorado School of

Mines, Golden, Colorado.

■ Native Copper
These jagged masses of native copper probably formed in highly fractured
rock where copper-bearing fluids could spread in many directions. This sam-
ple has been cleaned with acid to remove rock fragments that once surround-
ed it. This copper probably came from ore deposits of Bisbee, Arizona, that
formed about 170 million years ago.
Gift from William J. LeVeque, Department of Mathematics, Claremont Graduate School, Claremont, California.

■ Willemite, Zincite, and Franklinite
Zinc has been mined commercially in Franklin, New Jersey, since 1840. Frank-
linite, so named for the town, is an important ore of zinc and a minor iron-
manganese ore.The ores contain green willemite, deep red zincite, and black
franklinite, often with white or pink calcite. The ore also contains many un-
usual high-temperature minerals.

Ores from Franklin are highly fluorescent. The fluorescence occurs where
manganese ions have replaced other metallic ions in the minerals’ atomic
structures. Willemite, often used as a gemstone, fluoresces bright green or
bright yellowish-green in ultraviolet light when manganese has replaced
some of its zinc ions. It is named for King Willem I of the Netherlands (1772–
1843). Calcite fluoresces bright red when it contains ions of manganese, while
zincite takes on a red tint in ordinary light when it contains manganese.

29FIRST FLOOR EXHIBITS