Most slabs other than wooden slabs have the exact same properties as stone slabs

For example, a quartz slab takes slightly longer to mine than a quartz block, even though they should take the same time to mine. A quartz slab also has much higher blast resistance than a quartz block, rather than having the same blast resistance.

Every non-wooden slab except for purpur was previously listed under stone_slab and stone_slab2, which is probably the reason for this.