How common -- in real life -- are the resources needed for gunpowder?
I find it bothersome that my rivals can make gunpowder units immediately upon having the tech -- unless, of course, these materials are ridiculously common in real life. Then I understand. Otherwise, I'd like to see the comeback of, say, saltpeter from Civ III.
Gunpowder is actually quite easy to make = sulfur + charcoal +saltpeter (potassium nitrate)
Of the three the hardest one to obtain/purify is saltpeter although it occures naturally in the leech beds of organic waste piles (think rotting piles of used vegetation) - the key to poweful powder is the purity of the saltpeter and getting the ratios of S + C + KNO3 correct.
Resources: No new resources.