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.
District 01
East District 05 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.
District 04
District 04 quadBeryllium, feldspar, gemstone, lithium, quartz
Classic western-belt pegmatite country, worked since the 1800s and still turning up material.
District 02
District 02 quadBeryllium, feldspar, garnet, gemstone, mica
The historic heart of Maine gem mining. Tourmaline was first found in this country in the 1820s.
District 03
East District 05 quadBeryllium, feldspar, garnet, gemstone, mica
Multiple occurrences along the same belt as District 01, on the western edge of the pegmatite field.
District 06
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 - no coordinates. The underlying data comes from state survey records, and every site needs the landowner or the state before anyone puts a tool in the ground.