The zodiac sign Aquarius is associated with the birthdates between January 20 and February 18. People born under the sign of Aquarius are believed to have unique and innovative personalities. While there isn't a single gemstone universally associated with Aquarius, there are several gemstones that are often linked to this sign based on traditional astrology and metaphysical beliefs. Some gemstones associated with Aquarius include:

1. Amethyst: This purple quartz is often linked to Aquarius. It is believed to promote clarity of thought and enhance intuition.

2. Garnet: Garnet is another gemstone associated with Aquarius. It is thought to enhance creativity, courage, and positive energy.

3. Aquamarine: Given its name, aquamarine is often considered a suitable gemstone for Aquarius. It is believed to bring calmness and clarity to the wearer.

4. Moonstone: Moonstone is associated with intuition and is believed to bring balance to the emotions, making it a suitable choice for the sometimes eccentric and free-spirited Aquarian.

5. Labradorite: Labradorite is a mystical stone associated with transformation and spiritual growth. It is thought to resonate well with the Aquarian personality.

It's important to note that these associations are based on traditions, beliefs, and folklore. When choosing a gemstone, personal preference and individual resonance with the stone should be taken into account. If you're interested in using gemstones for their metaphysical properties, it's always a good idea to explore and find the one that feels right for you.