What does lava look like?
Lava takes many forms, depending upon its composition. The hottest lavas, such as basalts are very fluid, so flow very well and with great speed. Intermediate composition lavas such as andesite flow slower and cool quicker, and felsic lavas like rhyolite are coolest and flow slower and shorter distances. All lavas have a cooling skin. The type of skin is dependent upon the speed of the flow, and the temperature of the lava. Pahoehoe lavas move forwards in tongues or lobes and are characterized by a glassy, plastic skin, often with a wrinkled appearance. When the pahoehoe lava flow cools, it often solidifies to a smooth surface. These are typical of basalts. Ropy pahoehoe lava shows a surface texture which look like bundles of thick, twisted rope. Aa flows are emitted from a vent at high flow rates and are characteristic of viscous magmas such as rhyolite or andesite, or the cool end of basaltic flows. The hallmark of aa lava flows is the very rough surface it produces when it cools and
