Vermont has three state rocks: marble, slate and granite. That’s because, in the not so distant past, mines throughout the state carved out tons of the stuff for use around the country. Barre, known for its granite quarries, once employed scores of Irish and Italian immigrants. They turned the town from a 2,000-person village in 1830 to a bustling economic center boasting 11,754 residents by 1900. RockFire, now in its fifth year, celebrates that history. And the three-night festival of art, music and history takes the party right to the source: the abandoned granite quarries. Throughout the weekend, exhibits at the historic Socialist Labor Party Hall and the Vermont Granite Museum shed light on the town’s past. But the party really gets going on the pyrotechnic promenade of the Millstone Trails. Lit by hundreds of luminaries, the path leads to 10 stages featuring live, molten-metal pours by the Iron Guild, and musical performances from Bow Thayer and more.