Scored by mineral signature from the state occurrence dataset — beryllium and lithium weigh heaviest, because a pegmatite evolved enough to carry them is the one that carries gem tourmaline.
Newry
East Andover quadBeryllium, caesium, lithium, gemstone
The richest signature we scored in the whole state — caesium means pollucite, and pollucite only forms in the most evolved pegmatites, which is exactly where gem tourmaline lives.
Auburn
Minot quadBeryllium, feldspar, garnet, gemstone, lithium
Seven separate scored occurrences in one quadrangle. This is the Mount Apatite district — the largest cluster of gem-signature ground we found.
Greenwood
Greenwood quadBeryllium, feldspar, gemstone, lithium, quartz
Classic western-belt pegmatite country, worked since the 1800s and still turning up material.
West Paris
West Paris quadBeryllium, feldspar, garnet, gemstone, mica
The historic heart of Maine gem mining. Tourmaline was first found in this country in the 1820s.
Rumford
East Andover quadBeryllium, feldspar, garnet, gemstone, mica
Multiple occurrences along the same belt as Newry, on the western edge of the pegmatite field.
Stoneham
Speckled Mtn quadBeryllium, garnet, gemstone, feldspar, mica
Higher ground of the western belt, less picked over than the road-accessible workings.
Woolwich
Bath quadBeryllium, feldspar, gemstone, lithium, mica
A coastal-belt signature, which is worth knowing: gem pegmatites are not confined to the famous western county.
District and quadrangle names only — deliberately no coordinates. The underlying data is public, but a working dig spot is not, and a published pin invites both claim-jumping and readers walking onto land they have no permission for.