Gandalf carries Narya, one of the three Elven Rings of Power.
Narya is called the Ring of Fire and is associated with a red stone. Círdan the Shipwright originally possessed it, but he gave it to Gandalf when the wizard arrived in Middle-earth. Tolkien states that Narya helped its bearer resist weariness and inspired others to withstand evil.
The other two Elven Rings are Nenya, carried by Galadriel, and Vilya, carried by Elrond. All three were made by Celebrimbor in Eregion, independently of Sauron’s direct involvement. Because they were linked to the power of the One Ring, their use and fate remained connected to the larger history of the Rings.
A frequent mistake is assigning Nenya to Gandalf because its name resembles Narya. Nenya belongs to Galadriel, while Vilya is generally identified as the mightiest of the three and belongs to Elrond.