Plumbago Mountain is a pegmatite-hosted gem locality in Newry, Oxford County, Maine, in the United States. The mine, also referenced in the literature as the Plumbago Mine and the Plumbago Pit, is best known for the October 1972 pocket strike that produced gem-quality pink and bicolour elbaite tourmaline of exceptional size and colour. The find established Plumbago among the world-class American pegmatite localities and reinvigorated commercial and amateur prospecting across the Maine pegmatite province.

Geology

The Plumbago body is part of the broader Oxford County pegmatite field, a swarm of granitic pegmatites intruded into the surrounding metamorphic country rock during the Devonian. The pegmatites are lithium-cesium-tantalum (LCT) class, with mineralised pockets containing elbaite tourmaline, beryl, lepidolite, spodumene, and the accessory minerals typical of the type. Pockets at Plumbago have produced tourmaline crystals to over a metre in length, with prismatic terminations preserved and gem-quality cores yielding faceted stones in the multi-carat to tens-of-carats range.

The 1972 strike and historical production

The October 1972 pocket strike, made by Frank Perham and his crew, opened a single chamber yielding several hundred kilograms of gem and specimen tourmaline, with strong pink and bicolour material the dominant colour suite. The find was reported in trade press and remains one of the more celebrated American pegmatite discoveries of the late twentieth century. Subsequent mining at Plumbago and at the nearby Mount Mica, Bumpus, and Dunton workings has produced additional pockets, though none on the scale of the 1972 chamber.

Maine pegmatites have produced gem tourmaline since the nineteenth century, with the Mount Mica pocket of 1820 conventionally cited as the first reported gem tourmaline locality in North America. The Plumbago strike sits within this longer tradition and represents the continued productivity of the Oxford County field.

Material in the trade

Plumbago tourmaline appears most often in the collector market, with provenance documentation a meaningful price factor for both faceted stones and crystal specimens. Pink and bicolour material with the characteristic Plumbago colour profile — clean pink saturation with green-tipped or colourless transitions — commands a premium when accompanied by reliable mine attribution. Most Plumbago material in the trade dates from the 1972 strike or from subsequent twentieth-century working, with relatively little new production in recent decades.

In the trade

Buyers presented with stones described as Plumbago tourmaline should ask for the chain of custody and any contemporary documentation. Mine attribution from a reputable American dealer or directly from the Perham family records carries weight; vague references to Maine origin alone do not. The locality remains a draw for serious collectors, and well-documented Plumbago crystals occupy a recognisable place in the American mineralogical canon.

Further reading

• GIA Gems & Gemology — Maine pegmatite tourmaline articles
• International Gem Society — elbaite tourmaline reference
• American Gem Trade Association — North American coloured stone production