The modern birthstone(s) for October are Opal, Tourmaline. Traditional birthstone(s) are Opal, Aquamarine. Zultanite — gem-quality color-change diaspore from Türkiye — is not an official October birthstone.

Modern birthstone

The modern October birthstone list, established by the American National Association of Jewelers in 1912 and updated periodically since, includes: Opal, Tourmaline.

Traditional birthstone

The traditional birthstone list (drawing from older European and Polish gem-month associations) for October includes: Opal, Aquamarine.

Where Zultanite fits

Not an official October birthstone. October already includes the color-shifting opal; Zultanite is mineralogically unrelated but offers a different optical phenomenon (color change vs play-of-color).

How birthstone lists work

There is no single global authority on birthstones — modern, traditional, mystical (Tibetan), and Ayurvedic lists all differ. Zultanite was discovered too late (commercial production began in the early 2000s) to enter any of the historical lists.