To increase the amount of virtual memory go to Control Panel > System > Advanced > Performance > Settings > Advanced > Virtual Memory Change > Custom Size > adjust as needed. 2 times your physical RAM is a good minimum and 3 times your physical memory in MB is good for your maximum.
The three different types of lava differ in composition and flow rate. Rhyolitic lava is the slowest moving type of lava, since it has a high viscosity due to a high silica concentration. Basaltic lava is the fastest moving lava because of its low viscosity resulting from a low silica content.
Basalt, cider, Obsidian, foamed obsidian & others are types of ingeous rock, Volcanic Rock. Liquid rock is not always called lava. When the liquid rock is still underground it is called magma. The differences between magma and lava is basically made to make geological occurrences easier to understand and explain. A volcano erupts when there is sufficient pressure underground from magma that contains gas bubbles.