Minecraft wiki entry for Petrified_Oak_Slab, associated text: 1 Obtaining
1.1 Breaking
1.2 Crafting
1.3 Upgrading
2 Usage
2.1 Differences from normal slabs
3 Sounds
4 Data values
4.1 ID
4.2 Block states
5 History
5.1 Appearance changes
5.1.1 Block
5.1.2 Item
5.2 Info pertaining to all slabs
5.3 Data history
6 Issues
7 Gallery