Why is My Aquamarine not Blue?

Aquamarine is a popular gemstone known for its light blue or blue-green color. However, some aquamarines can appear more greenish or almost colorless. If your aquamarine doesn’t have the deep blue hue you expect, there are a few possible reasons.

The Color of Natural Aquamarine

Aquamarine belongs to the beryl family, which also includes emeralds and morganite. The color in beryl gems comes from trace amounts of iron. Iron ions produce blues and greens depending on their oxidation state. More iron equals more intense color.

Natural aquamarine forms in granite rock and pegmatites. The conditions during formation impact the iron content and final color. Aquamarines with less iron will be very pale or even clear. While beautiful, these lack the striking blue so coveted in aquamarine.

Heat Treatment

Heating is a common treatment used to produce blue aquamarines. Gems are heated to between 450-470°C for several hours. This process causes the iron ions to convert to the oxidation state that displays blue.

Stones that are originally very pale or green will turn sky blue with heat treatment. However, the results are not permanent. Over time and exposure to light, heat treated aquamarines often fade back to their original color.

While stable, natural blue aquamarines are rare and expensive. Heat treatment allows jewelers to offer more affordable blue gems. Make sure any heated aquamarine has full disclosure so you understand the potential for color change.

Cut Quality

Even naturally blue aquamarines can appear washed out if the cut is poor. Aquamarine has strong pleochroism, meaning the color intensity depends on the viewing angle. A well-cut gem displays an even color from any direction.

With a bad cut, light leaks out from the sides instead of reflecting back to the viewer. This causes the gem to look paler. Check your aquamarine in different lighting and from different angles. Improved brightness indicates better cutting.

Mounting Choices

The metal you choose for an aquamarine ring or pendant also impacts its color. Yellow gold or brass creates warm reflections that can subdue the blue overtones. Platinum, white gold, and sterling silver provide cooler and crisper contrast to allow the blue to shine.

Additionally, make sure the stone is securely mounted and not loose in the setting. Movement inside the mounting causes light to reflect irregularly through the stone, reducing its color saturation.

In summary, several factors like iron content, heating, cut quality, and mounting influence aquamarine color. A pale aquamarine can still be gorgeous, especially if you select an appropriate white metal setting. But if you prefer a vivid blue, consult a gemologist to find an untreated stone with expert cutting. With the right aquamarine, you’ll have a breathtaking ocean blue gem.