Aquamarine and Diamond Ring. Aquamarine is the birthstone of March, and is famous for its pale blue to light green colour palette, as well as the transparency and size of its crystals. The aquamarine at the centre of this ring shows these attributes beautifully - its colour is a fine light blue, and at 17 carats it’s a big stone, with astonishing clarity, shown off beautifully by its emerald cut. With its cool hues lending themselves so well to geometric cuts like this, it’s no wonder that aquamarine was tremendously popular during the Art Deco period, with jewellers such as Cartier devoting entire suites of jewels to them. Mounted within icy geometric shoulders set with single-cut diamonds, this aquamarine jewel is a great statement piece.