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.
Different types of lava have different chemical compositions. Since not all rocks have the same chemical composition and lava is just liquid rock, it does not have an official formula. Most rocks (and therefore lava) are made up of a combination of the elements Oxygen, Silicon, Aluminum, Iron, Calcium, Sodium, Potassium, and Magnesium. Different types of rocks (and lava) have different amounts of these elements. Therefore, there is not a specific chemical formula for lava. Different types of lava have different chemical compositions. Since not all rocks have the same chemical composition and lava is just liquid rock, it does not have an official formula.