Some people think that exploring caves gives you lots of matterial. That is partly true you can get lots of iron and coal. But,it is really hard to find diamonds, lapiz luza, emeralds, and redstone that way.

These are some ways you can actually get some of these rare materials:

1. Explore crevices, those big large slices in the earth. (Dangerous)

2. Go explore & loot a nether fortress, a stronghold, a mine, or a blacksmith's house. (Can be dangerous)

3. Make a 2 block high, 3 block width staircase until you meet bedrock. (Barely any danger)