All minerals are crystalline solids. Minerals fracture along planes of weak atomic bonds in their structures. Cinder cones commonly erupt pyroclastic material T F 5. Fissure eruptions generally produce rhyolite lava flows. The intensity and type of weathering found in a given area depends in part on the slope of the ground and its drainage.
Pahoehoe refers to the smooth, billowy or ropy surfaces on lava flows.
Pahoehoe crust forms on relatively high viscosity lava. Crystal settling causes low density minerals to sink to the bottom of plutons. The type of soil in an area is vital in determining the type and suitability of septic systems for homes built in that area. Glassy igneous rocks are evidence of extremely slow cooling of the magma. Pillow lava form from under water volcanic eruptions.