Keweenaw minerals II

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VIRTUALFIELD TRIP TO THE KEWEENAW PENINSULA, MICHIGAN - MINERALOGY II

The probability of finding a good cabinet sized specimen of many of the mineralsfrom the district is now extremely low. But minerals do exist in micro-sizedcrystals that can best be appreciated under the microscope. Crystals of thissize are more perfect than their larger brothers, and many minerals in thedistrict are onlyknown to occur as small crystals. These specimens also provide a view into the world of crystalgrowth and the environments in which the ore formed.

The specimenson this page were all photographed by Dan Behnke, and unless otherwise noted arefrom his mineral collection.

Copper on epidote, Iroquois mine, Keweenaw County. Crystal is 0.6 mm high.

Copper wires on prehnite, Osceola mine, Houghton County. Wires are 5.5 mm long.

Spiral hoppered copper crystals, Caledonia mine, Ontonagon County. Richard Whiteman specimen. 6.5 mm across central hopper.

Silver cubes on copper, Caledonia mine, Ontonagon County. Crystals to 0.1 mm. Note that the majority of these crystals have epitaxially (crystallographically aligned) grown on the underlying copper

Cuprite octahedron, Devil's Washtub, Keweenaw County. Crystal is 0.4 mm high.

Malachite "bow tie" on chrysocolla, Osceola Lode, Houghton County. Malachite group is 0.7 mm high.

Malachite ribbon on azurite. Isle Royale mine, Houghton County. Thomas Rosemeyer specimen. Curl diameter is 1.1 mm.

Kinoite in quartz crystal, Laurium mine, Houghton County. Quartz crystal is 2.8 mm. long.

Gephardtite, Caledonia mine, Ontonagon County. Crystal is 0.3 mm. tall.

Calcite crystal with inclusions of copper, Caledonia mine, Ontonagon County. Calcite crystal is 5.7 mm high.

Natrolite, Copper Falls mine, Keweenaw County. Crystals are 1.3 mm long.

MacFallite, Manganese Mine, Keweenaw County. Crystals are 0.6 mm high. Although copper and silver were the elements mined in the area, several other minerals occur in other types of deposits in the district, or as gangue minerals in the copper deposits.

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