Aquamarine is a popular gemstone known for its light blue to bluish-green color. However, some aquamarines can appear more greenish or even nearly colorless. If your aquamarine doesn’t have the deep blue hue you expected, there are a few possible reasons.
The Cause of Color in Aquamarine
The color of aquamarine is determined by trace amounts of iron within the mineral beryl. The iron acts as a chromophore, which is a chemical compound that provides color. Specifically, iron can produce blues and greens in gemstones. The more iron that is present, the darker and more blue the aquamarine will appear. Less iron results in a paler or greener aquamarine.
The saturation of the color also depends on the gemstone’s geological formation. Aquamarines formed in granite pegmatites tend to have a richer color than those formed in marble. The amount of heat and pressure during formation impacts the distribution of iron ions, and thus the depth of color.
Cut and Clarity Affect Color
The cut quality and clarity of an aquamarine also influence its apparent color. Well-cut aquamarines allow more light to pass through, intensifying the blue hue. Poor cut quality and numerous inclusions can diminish the color by diffusing and reflecting light.
Very pale aquamarines are sometimes heat treated to produce or improve blue coloration. This process causes some of the iron ions to adopt a different atomic structure, increasing their light absorption and producing more vibrant blue tones.
Natural Color Variations
Not all aquamarines will display a rich blue color, even with quality cutting and few inclusions. Some natural stones have lower iron content or trace elements that shift the color toward green or nearly colorless. There are a few possible reasons:
- Low iron content – Less chromophore means less blue color
- High manganese – Manganese ions produce yellow and can cancel out blue tones
- Radiation exposure – Can reduce iron ions and lighten color
- Oxidizing conditions – Causes iron ions to shift and lose color
The location where the aquamarine formed greatly influences these factors. For example, gems mined in Nigeria, Mozambique, and Madagascar usually have a very light color. Meanwhile, aquamarines from Pakistan and Afghanistan are known for their deep blue hues due to ideal conditions promoting high iron content.
How Blue Should Aquamarine Be?
Aquamarine exists on a continuous color spectrum from very light blue-green to a deep ocean blue. There are no objective standards about how blue it “should” be. Light-toned aquamarines are not inferior, they are simply characteristic of certain geological formations.
That said, the most valued and expensive aquamarines exhibit a vivid blue, like the color of the ocean or a blue topaz. Here is a table comparing the price and desirability of different aquamarine color varieties:
| Color Variety | Price / Desirability |
|---|---|
| Vivid blue | Most expensive, highly desirable |
| Sky blue | Less expensive but still desirable |
| Greenish-blue | Lower cost, moderately desirable |
| Seafoam green | Lower value and demand |
| Pale green | Least expensive, lower demand |
While vivid blues are the most prized, even paler aquamarines have their beauty. Their lower cost also makes them more affordable for jewelry.
Factors that Impact Aquamarine Value
Beyond color, aquamarines are evaluated on several factors that determine their overall quality and value:
- Clarity – How transparent and free of inclusions. Eye-clean stones are preferred.
- Cut – How well proportioned and polished to maximize light return and beauty.
- Carat – The exact weight and size. Large aquamarines are increasingly rare.
- Source – Geographical origin influences color saturation and perceived value.
- Treatment – Enhancements like heating reduce value compared to natural gems.
An aquamarine that is less blue but has excellent clarity, skilled cutting, and larger size could be worth more than a vividly blue stone with flaws and dullness. As with any gemstone purchase, it is important to balance all value factors.
Should I Be Concerned About My Aquamarine’s Color?
If you recently purchased an aquamarine that is less blue than expected, don’t be too quick to assume it is faulty or inferior. As explained above, many natural factors affect the hue. Unless the color seems artificially enhanced, it is likely just a result of the stone’s unique geological origins.
However, if the color seems very off, evaluating the stone’s quality in other aspects like cut and clarity may reveal an inferior gem. Poor cutting could prevent blue tones from being reflected. Significant inclusions can also muddle the color. Inspect the stone closely under varied lighting conditions to assess.
You can also ask a gemologist to review and verify the aquamarine. Advanced testing can detect any color treatments and identify geographical traits that give clues to the expected color range.
Lastly, check your expectations and any description provided by the seller. Vivid blue is ideal but not guaranteed, especially with aquamarines from certain regions. As long as there is some blue or blue-green element and the stone is natural, minor color differences should not be a major concern.
Improving the Color of Pale Aquamarines
If you remain dissatisfied with your aquamarine’s color, there are a few options to enhance the tone:
- New cut – Re-cutting and polishing can improve light handling and make color more vibrant.
- Heat treatment – Professionally heating to 400-450°C can induce more blue color.
- Dye or irradiation – Artificial color enhancement but damages value.
- Different setting – A white metal setting reflects more blue light.
Re-cutting is the safest option for improving appearance while retaining value. Heating should only be done carefully by a professional gemologist. Artificial dyeing or radiation exposure should be avoided as they permanently damage the stone.
Picking the Right Aquamarine
Not all aquamarines exhibit that striking light blue that first comes to mind. But gems on the paler end of the spectrum can offer an elegant and more affordable alternative. The most important considerations are:
- Prefer natural color, even if paler
- Evaluate cut quality, clarity, size as well as color
- Review any description from the seller
- Understand the typical color range from that source location
- Consider re-cutting or heating if color is unsatisfactory
With knowledge of the factors that influence aquamarine color, you can have realistic expectations and appreciate these gems across their full range of charming hues.
Conclusion
Aquamarine color varies naturally based on subtle geological factors. While deep blue is the ideal, lighter blue-green is more common and also has beauty. Careful evaluation of cut, clarity and setting can help maximize the appearance of color. With realistic expectations, you can pick an aquamarine you will enjoy regardless of its exact shade.
