# Ruby of the War Mage > [!info] Item Details > | | | > |---|---| > | **Category** | Wondrous Items | > | **Rarity** | Common | > | **Attunement** | Yes | > | **Source** | XGtE p.139 | --- ## Description Etched with eldritch runes, this 1-inch-diameter ruby allows you to use a simple or martial weapon as a spellcasting focus. Attach the ruby to the weapon by pressing it against the weapon for at least 10 minutes. A weapon can have only one ruby attached to it. While the ruby is attached to a weapon you are holding, you can use that weapon as a spellcasting focus for your spells. --- ## Properties - Press the ruby to a simple or martial weapon for **10 minutes** to attach it permanently. - While holding the weapon, use it as a **spellcasting focus**. - A weapon can only have **one ruby** attached. - Requires attunement by a **spellcaster**.