March Birthstone Aquamarine: Aquamarine has been associated with March as its birthstone in the modern era. This birthstone rule on two zodiacs of March – Pisces and Aries, with the ruling planets Neptune and Mars. Aquamarine is a gem that calms the wearer's heart and clears her mind wherein bringing peace and tranquility within her. It is also beneficial when one is trying to articulate her suppressed emotions and get in touch with the real world through the truth.