Method 1: Crafting Table
Place 3 Any item such as Chiseled Quartz Block in a Crafting Table to make 6 Quartz Slabs.
6 How to Make a Quartz Slab in Minecraft
Use this simple recipe to make a Quartz Slab in Minecraft. You can see the exact ingredients, recipe layout, and workstation below.
Quartz Slab recipe
Follow the recipe below. The pattern must use the correct slots when the recipe is shaped.
6 
Method 2: Stonecutter
Use 1 Quartz Block in a Stonecutter to make 2 Quartz Slabs.
2 About this Minecraft recipe
This page shows the vanilla recipe for Quartz Slab. It includes the exact ingredients, recipe layout, required workstation, and amount produced.
The data comes from Minecraft Java 26.2. Recipes can change in later game versions, so check the version you play before crafting.