The mountains and valleys of New Hampshire are rich with mineral formations. From the southwest corner of the state near Keene to the northern Canadian border near Littleton there are fascinating deposits of a variety of minerals.
One of these deposits is known as the Littleton Formation which was formed during the Devonian era approximately 300,000,000 years ago. The mining of these mineral deposits has been an important part of New Hampshire history from prehistoric eras to the present.
The Ruggles Mine, in Grafton N.H., is part of the Littleton Formation and has a rich mining and geological history. It is the oldest and largest mine of its kind in the United States. Minerals such as Mica, Feldspar, Beryl, and Uranium were mined at Ruggles for 175 years.