Tourmaline is a complex boron silicate mineral known for displaying a wider array of colors than almost any other gemstone. The crystals are typically prismatic with distinct vertical striations and can range from black to vibrant shades of green, blue, and pink. Maine has a long-standing global reputation as a significant source for fine, gem-quality tourmaline, cemented by discoveries like the major 1972 find.
The Host Rocks: Why Tourmaline Thrives in Maine
The presence of gem-quality tourmaline in Maine is directly linked to granite pegmatite, a specific type of igneous rock. Pegmatites are characterized by their extremely coarse grain size, often containing crystals several inches or even feet long. This texture results from the slow cooling of residual magma rich in water and volatile elements like boron and lithium.
The high concentration of dissolved fluids in the late-stage magma allowed mineral components to move freely, resulting in the growth of large, well-formed crystals. These volatile-rich fluids also created open cavities or “pockets” within the pegmatite veins. The most prized, colored tourmaline—the lithium-rich variety called elbaite—crystallized within these pockets during a high-temperature hydrothermal phase. This geological environment, found in western Maine, provided the conditions for growing large, transparent crystals suitable for faceting.
Specific Maine Localities for Tourmaline Hunting
The primary region for tourmaline hunting in Maine is Oxford County, situated in the western mountains. This area includes the towns of Paris, Newry, Stoneham, and Greenwood, all well-known for their pegmatite deposits. The history of finds dates back to the 1820 discovery at Mount Mica in Paris.
Mount Mica is the oldest continually operating gem mine in the United States and has produced spectacular bi-color and watermelon tourmaline specimens. While the active mine is not always open for public digging, nearby commercial operations sometimes offer field trips to the mine dumps or provide processed material. The Dunton Mine on Plumbago Mountain in Newry is another historically important site, famous for the massive 1972 pocket discovery.
For the general rockhound, the most reliable way to hunt for tourmaline is through commercial or fee-based collecting operations. Places like Dig Maine Gems in West Paris offer guided trips to mine sites or allow visitors to sift through mine tailings. These commercial sites ensure access to material from productive areas and provide the necessary equipment and guidance. The scattered waste piles, or dumps, of older pegmatite quarries across Oxford County also remain a source for casual collectors who secure permission from landowners.
Necessary Tools and Collection Methods
The most common method for finding tourmaline in Maine involves working through the mine dumps, which are piles of rock discarded during past quarrying operations. Essential equipment includes a sturdy geology hammer and a crack hammer, used with a steel chisel to break apart larger pieces of matrix rock. A small hand shovel or trowel is helpful for digging through the loose soil and gravel.
Safety equipment includes work gloves, eye protection, and durable boots. Many collectors also employ a screen or sifter to process finer material and gravel, often using sluicing, where water helps wash away dirt and reveal crystals. To identify a potential tourmaline find, look for a glassy luster and a distinct prismatic crystal shape, often with vertical striations. The mineral’s hardness (7 to 7.5 on the Mohs scale) helps it resist scratching, and it lacks the distinct cleavage planes found in many other minerals.
Regulations and Ethical Collection Practices
Adhering to local regulations and ethical practices is necessary when searching for tourmaline in Maine. The most important rule is obtaining explicit permission before entering any private land, as trespassing laws are strictly enforced. Since many productive historical mine sites are privately owned or leased, prior contact with the owner is mandatory.
For collecting on State-owned public lands, casual mineral collecting for hobby or educational purposes does not require a special permit from the Maine Geological Survey. However, the removal of any natural material is strictly prohibited in all Maine State Parks. Collectors should always confirm the status of the land before digging and avoid areas designated as mineral claims. Ethical collecting means minimizing environmental impact, including filling in any holes or pits created during the search and packing out all trash and debris.