Gunpowder is an amazing advancement in technology; everything from ancient hunting rifles to automatic machine guns use it. It can be used to launch large projectiles such as cannon balls, or it can be used for less murderous purposes. Blasting can greatly speed up the mining process, and the controlled explosions can be used to move large or dangerous objects.
Gunpowder is made up of three parts. Potassium Nitrate, Charcoal, and sulphur. Measured by weights, the percentages are as follows: 75% potassium nitrate, 15% charcoal and 10% sulfur. Charcoal can easily be made, but finding sulfur or potassium nitrate can prove a little more challenging.
Potassium nitrate is also known as saltpeter. To make it requires several months, and involves many biological components. The simplest method of creating saltpeter is to put stale urine into a container holding straw hay. This is allowed to sit and decompose for several months, after which you use water to wash the chemical salts out from the remaining straw. You then filter this "salty" liquid through wood ashes and leave the remains in the sun to dry.
Sulphur is easily identifiable by it's yellowish color and scent of rotten eggs. When ignited, it melts into a blood-red liquid and burns with a bluish flame. Elemental sulfur can be found near hot springs and volcanic regions in many parts of the world, especially along the Pacific Ring of Fire. Such volcanic deposits are currently mined in Indonesia, Chile, and Japan. Sicily is also famous (or will be famous) for its sulfur mines.
To extract the sulfur from it's rocky entombment, place bricks of sulfur in kilns near a sloping hillside. Make sure there are gaps between each brick to ensure airflow. Ignite the bricks and the heat will cause the sulfur to melt and run down the hill, where it can be collected. This sulfur must then be further purified using distillation.
Heat the sulfur to the point it begins to evaporate. The sulfur gas will rise where it should condense on a sloping surface and run into a separate collecting container. This is purified sulfur.citation needed
Now that you have all of the ingredients, you can begin to make gun powder. You might want to use a Ball Mill to simplify this process, but a simple mortar and pestle (and several days worth of grinding) can do in a pinch.
First, combine and mill the charcoal and sulphur together for about 4 hours. Once this is well ground, add in the potassium nitrate and mill the entire mixture for 24 to 48 hours. The finer the powder, the more effective (and explosive) the burn.