That depends on who you ask. Ask the Romans, and they'll tell you to carve the figure of frog onto the gemstone, and it becomes a stone that reconciles enemies and turns them into friends.
People also believe that the Romans considered aquamarine the perfect gift for the bride from the groom after their first night of consummation.
From there, soldiers and sailors use aquamarine because they believe that it renders them invincible and keeps the ocean at bay.
All-in-all, it's an all-purpose gemstone that majorly reflects what you want it to.