New Hampshire Rock and Minerals

New Hampshire has a large variety of rocks and minerals.

This is due mostly to the pegmatites that comprise a large portion of New Hampshire's surface.

The igneous and metamorphic rocks were worn down by glacial activity and then by weathering from rivers and streams, exposing interesting rocks and minerals in the pegmatites. The best places to rockhound in New Hampshire are where pegmatite minerals are exposed in outcrops on hillsides, in old quarries, in gravel beds near streams and rivers, and in mountain ridges. These pegmatites often produce large crystals of amethyst, tourmaline, apatite, and quartz.

New Hampshire is known as "the Granite State", but less than half of the state is actually underlain by granite. Most of it is schist or gneiss, both of which are metamorphic rocks. The White Mountains of the Appalachians are the dominating geological feature of New Hampshire, with the summit of Mount Washington being the highest point in the northeastern United States. The White Mountains occupy the north-central part of the state, an area of some noteworthy mineral finds. Above the mountains is a region of ridges and valleys, and south of them is the plateau characteristics of the New England upland. Glaciers have stripped the rocky granite highlands and created many lakes.

Gold was discovered in Lyman, New Hampshire in 1864, sparking a minor rush. Several small mines soon opened in the Bath, N.H., area, but none of these mines operated for very long. Gold has been identified in placer deposits, quartz veins and in metamorphosed conglomerate, especially the Clough Formation in the western side of the state.

The USGS records 260 active mines in New Hampshire and the primary occurrences are beryllium, feldspar, mica, silica, and copper.

Popular with rockhounds is the Moat Mountain Mineral Site in the White Mountain National Forest, near Conroy, New Hampshire, where you can dig with a permit. The Moat Mountain Mineral Site is located on the contact zone of two rock units: the Conway granite and Moat volcanics. Quartz, amethyst (purple), and even fluorite crystals have been found here, but the most commonly found is small smoky quartz crystals.

Before venturing out-do some research on where and what you can collect. Remember you must have permission to collect on private property.

See my page on Rockhounding Rules for general information on the rules of collecting rocks on various lands.