Aquamarine: Sea Blue Beryl

Aquamarine is blue beryl, coloured by iron. Where emerald is full of inclusions, aquamarine is usually clean and clear, so it is cut into larger, brighter stones that show off their transparency. The colour ranges from a pale glacier tint to a deeper teal blue.

Pakistan's northern mountains are one of the world's known sources. Crystals from the Shigar valley near Skardu are admired by collectors for their size and clarity, and many fine aquamarines on the wider market trace back to the Karakoram. Origin needs a lab to confirm, so we only state it when we know it.

What to choose

The deeper and purer the blue, the higher the price per carat. Many pale green blue stones are gently heated to remove the green, which is stable and common. Because the colour is light, size helps: below about 2 carats, aquamarine can look nearly colourless, while 5 carats and up shows the blue clearly. Long emerald cuts and ovals suit it well.

Aquamarine has no strong place in the older astrology traditions of the region, so most buyers here choose it for its looks: a gift, a birthstone for March, or a cool contrast to yellow gold.

At 7.5 to 8 on the hardness scale and without emerald's fragility, aquamarine is comfortable in a ring with claws or a bezel. It can still pick up scratches on granite worktops over time. Clean it in warm soapy water; it is one of the easier gems to look after.