This specimen features half of a beautiful Datolite nodule from the Caledonia Mine in Mass City Michigan. The specimen face has been polished to a high luster. On the back of the piece you can also see some of the iron staining that helps give this Datolite its color. 

This specimen measures 34 mm x 24 mm x 10 mm.

Massive Datolite in nodules such as this specimen has only been found on the Keweenaw Peninsula and the North Shore of Minnesota. 

History of the Caledonia Mine

The Caledonia Mining Company was organized in 1863 after purchasing the Nebraska and Kansas Mining Company properties. Operations continued until 1871, when Caledonia and the Flintsteel Copper Coompany merged together. In 1872, the mine closed having produced approximately 903,000 pounds of refined copper. From 1873 to 1881, the mine was tributed and another 330,000 pounds of copper was produced, including one mass weighing 40 tons. The mine was dormant until 1937, when Calumet & Hecla reopened the No. 4 adit for exploration, but stopped the project due to World War 2. In 1950, C&H returned to continue exploration, drifting, and stoping. Between 1951 and 1958, C&H removed approximately 5.5 million pounds of refined copper from the No. 4 adit. In 1985, Red Metal Explorations acquired the Caledonia Mine and conducted exploration of the property until 2013, when Evergreen Explorations purchased the property. The mine was the centerpiece for a week long series of mineral collecting field trips in August put on by local organizations. The mine is exceptional for copper, silver, and datolite, as well as a range of microminerals.