Diamonds are near lava Gold is near water Redstone is mostly near lava Iron is most likely anywhere Sand is near water Cobblestone is everywhere
Anyone could of made that! He could at least of made rough layers in where to find them e.g Diamond is located between bedrock and layer 15. but most commonly people find diamond at around 10-15. It is usually not too far from Lava. But this isn't always the case.