Aquamarine: What type of stone is it, how is it formed, and where is it found? | List of aquamarines for sale
- Carolina Vivas-Serna
- Oct 13
- 5 min read
Updated: 5 days ago
With its captivating color, aquamarine has been one of the most prized gemstones throughout history.
Its name, derived from the Latin "aqua marina" (sea water), is a true reflection of its beauty.
So, if you want to learn more about this stone, continue reading this guide we created for you, where you will find:
1. What is aquamarine?
Aquamarine is a gemstone, and is the blue to blue-green variety of the mineral beryl.
This means it is related to other gems such as emerald (green beryl), morganite (pink beryl), and heliodor (yellow beryl).
Aquamarine's distinctive hue is due to the presence of traces of iron within its crystal structure.
Furthermore, its popularity in jewelry is quite high; therefore, it is a frequent choice for rings, earrings, necklaces, and other high-end pieces.
2. Properties of aquamarine
Below you can find a summary of the most important characteristics of aquamarine:
Property | Description |
|---|---|
Mineral type | Beryl |
Chemical composition | Beryllium aluminum cyclosilicate (Be3Al2Si6O18) |
Hardness (Mohs scale) | 7.5 to 8 |
Density | 2.68 to 2.74 g/cm³ |
Luster | Vitreous (glass-like) |
What gives it its color | Traces of ferrous iron (Fe2+) |
According to the Mohs scale, aquamarine is a durable stone, suitable for everyday use in jewelry.
However, we recommend proper care to preserve its beauty over time.
3. How is aquamarine formed?
Aquamarine formation occurs deep within the Earth's crust:
It originates primarily in igneous rocks called pegmatites, which are the result of the final crystallization of magma.
This is what happens:
During the final stages of magma cooling, elements such as beryllium and aluminum are not incorporated into the formation of minerals.
Instead, they concentrate in residual fluids that force their way through cavities and fissures in the rocks.
These residual fluids then slowly cool, creating ideal conditions for the growth of beryl crystals.
The presence of iron is the determining factor for these crystals to acquire the characteristic blue color of aquamarine.
4. Where is aquamarine found?
Aquamarine is found in various parts of the world, but some countries are renowned for the quality and quantity of their gems.
Historically and currently, the most prestigious aquamarine deposits are found in:
Brazil: This has long been the most important source of high-quality aquamarines. The state of Minas Gerais is famous for producing stones of large size and exceptional clarity.
Pakistan: In the Gilgit-Baltistan region of the Karakoram Mountains, aquamarines with an intense blue color and outstanding transparency are mined.
Mozambique: In recent years, this country has become a key producer of high-quality aquamarines, known for their deep, saturated blue color, which often requires no heat treatment.
Madagascar: This country is renowned for producing aquamarines in a wide range of hues.
Other high-quality aquamarine deposits include countries such as Nigeria, Zambia, Afghanistan, and Russia.
5. Types of aquamarine
Generally speaking, aquamarines are classified based on their color.
However, they can also be classified according to their origin, which is often associated with a particular hue.
Types of aquamarine by color:
According to their color, aquamarines are classified as follows:
Light or pale blue: This is the most common and affordable color.
Greenish blue: A natural hue that is often heat-treated to remove the greenish component.
Sky blue: A very popular light and bright blue color.
Deep or saturated blue: This is the rarest and most valuable hue; the intensity of the color is a key factor in determining the price of aquamarine.
Types of aquamarine by location:
According to their location, aquamarines can be classified as follows:
Santa Maria Aquamarine: Originally from the Santa Maria de Itabira mine in Brazil, this term is now used in the trade to describe aquamarines with a deep, intense, and highly saturated blue color, regardless of their origin. They are the most valuable and coveted.
Espirito Santo Aquamarine: These are aquamarines from the state of Espirito Santo in Brazil, which usually have a more subtle and delicate blue hue.
Mozambique Aquamarine: They are characterized by their beautiful intense blue color, often compared to the color of "Santa Maria" gemstones.
6. What treatments are given to aquamarine?
Many aquamarines undergo treatments to improve their appearance, especially their color.
It is essential that these treatments be declared by the seller, as they can affect the gem's value.
Treatment | Process Description | Effect on the Gem | Effect on Value |
|---|---|---|---|
Heat Treatment | The stone is heated to temperatures generally between 400-450°C. | This eliminates any yellowish or greenish tones, producing a purer and more stable blue color. | This treatment is very common and widely accepted in the market. It does not significantly decrease the value of the stone, as the result is fairly stable over time. An aquamarine with a good color obtained by heat treatment can be more valuable than a pale, untreated stone. |
Irradiation | The gem is exposed to radiation to intensify the blue color. | It can produce a very intense blue color; however, it can be unstable. | Due to the instability of the color, this treatment can significantly decrease the stone's value. Irradiation is not common with quality aquamarines. |
Fracture Filling | Surface fissures are filled with colorless resins or oils. | It improves the apparent clarity of the gem. | The presence of this treatment can decrease the value of the stone and compromise its durability. It is rare in high-quality aquamarines. |
It's important to note that aquamarines with a natural, intense blue color, without any treatment, are extremely rare and fetch the highest prices on the market.
7. What factors define the quality of an aquamarine?
When purchasing an aquamarine, it is crucial that you evaluate four main factors, known as the "4 Cs" in gemology:
Color, Clarity, Cut, and Carat.
Color
This is the most important factor in valuing an aquamarine.
The most desired color is a deep, saturated blue, with as few greenish hues as possible.
Pale or very light blue stones are more common and therefore more affordable.
Clarity
Many of the faceted aquamarines found on the market are "eye-clean," meaning they have no visible inclusions.
High clarity is a standard for this gem, while the presence of visible inclusions decreases its value.
Cut
The quality of the cut (the gem's cut) is essential to enhance the beauty of the aquamarine.
Therefore, a well-proportioned and well-executed cut is essential to maximize the stone's brilliance and color.
Emerald and oval cuts are very popular, but they can be found in a wide variety of shapes.
Carat Weight
The weight of a gemstone is measured in carats (1 carat = 0.2 grams).
Unlike some other stones, aquamarines can be found in large sizes.
As the size increases, the price per carat also tends to increase, especially if the color and clarity are exceptional.
As you can see, aquamarine is a gemstone of great beauty and durability.
When making a purchasing decision, pay attention to the intensity and purity of its blue color, the absence of visible inclusions, and the quality of its cut.
Also, remember to ask if the aquamarine has received any type of treatment.
We hope that with this guide, you can make more informed decisions when purchasing an aquamarine.
