These glass droplets form during fountaining eruptions of fluid (low-viscosity) basaltic lava. As the lava is sprayed into the air, surface tension pulls the molten liquid into tiny spheres or teardrops. If the wind is strong, these droplets can be stretched into long, thin threads known as Pele’s Hair. Pele’s Tears provide geologists with “frozen” snapshots of the lava’s chemistry at the moment of eruption. They are often found caught in cracks in the rock or in downwind areas near vents like Hawaii’s Kilauea.