Aquamarine

The color of aquamarine has connected it to the element of water and to the sea in particular. From the third century BC, Greeks and Romans used the stone as a protective charm for overseas journeys, together with cameos carved with images of Poseidon, god of the sea, with his trident. Aquamarine was also a symbol of happiness and hope and like emerald, was associated with love and friendship.
Aquamarine can provide a significant boost to the immune system. It has a cleansing action that, in combination with its ability to stimulate the thymus gland, can help clear infection from the body. 
The throat chakra is energized by this crystal, encouraging creative expression and communication skills. There is also an improvement in mood, with an increase in hopefulness, optimism and inspiration.