Aquamarine value evaluation | Buyer explains color, Santa Maria, and evaluation criteria
Aquamarine is a gemstone whose value varies greatly depending on its color intensity. In this article, we will explain the evaluation criteria for aquamarine, the Santa Maria color, how to distinguish it from similar stones, and important points for sales appraisal, based on primary information from gemological institutions such as GIA and the appraisal practices of jewelry specialty store SELBY. This article is for those who are considering purchasing or want to know the value of the aquamarine they own.
*"Value" in this article refers to the price evaluated in the market/assessment (assessed price/distribution price).
Takazo Saito(Selby Co., Ltd.)
Buyer for the Komehei Group's only company specializing in jewelry. In addition to supervising the e-commerce, SNS, loose, and product production departments, he is also in charge of purchasing rare stones. He specializes in determining authenticity and evaluating value, and works to protect consumers and improve market transparency by disseminating gemological information.
- What is the value of aquamarine?“Color intensity and purity” are the most important. The darker and clearer the blue, the higher the evaluation.
- The highest color is"Santa Maria Color"This is called a stone, and the price can be several times higher than that of a light-colored stone of the same size.
- The standard for transparency is that no inclusions are visible to the naked eye (eye-clean). Heat treatment is common and is thought to have little effect on value.
- It is easily confused with blue topaz and glass.The presence or absence of a certificate of authenticity affects the appraised value.Sometimes it happens
- In the second-hand market, light-colored small stones tend to be valued mainly for the bare metal, while dark-colored large stones tend to be evaluated for the stone itself.
- What is aquamarine? Basic information as a gemstone
- Five evaluation criteria to determine the value of aquamarine
- What is the highest peak “Santa Maria Color”?
- Relationship between production area and value
- How to distinguish between similar stones and fakes
- Actual evaluation and appraisal in the used market
- Points to note when purchasing
- Points that are highly valued when selling
- Frequently asked questions (FAQ)
- Summary
What is aquamarine? Basic information as a gemstone
Aquamarine is a pale blue to blue-green gemstone that belongs to the same mineral group as emeralds called beryl.The color is caused by trace amounts of iron contained in the crystals, and with a Mohs hardness of 7.5 to 8, it is hard enough to withstand everyday use. The name comes from the Latin word "aqua marina" and is known worldwide as the birthstone for March.
The basic gemological data is as follows (based on public information from GIA Handbook of Mineralogy).
| Item | Content |
|---|---|
| mineral species | Beryl (beryl) |
| chemical composition | Be3Al2Si6O18(silicate minerals containing beryllium) |
| mohs hardness | 7.5〜8 |
| refractive index | Approximately 1.577~1.583 |
| specific gravity | Approximately 2.68~2.74 |
| cause of color | Trace amounts of iron (Fe2+） |
| birthstone | March |
Beryl is also called emerald if it turns green with chromium or vanadium, morganite if it turns pink with manganese, and heliodor if it turns yellow depending on the state of iron. Aquamarine is a beryl that is relatively large and highly transparent crystals are easily produced, so it is a gemstone that has a wide range of value depending on its quality.
Five evaluation criteria to determine the value of aquamarine
The value of aquamarine is determined by five factors: color, clarity, carat, cut, and treatment, with color intensity and purity determining the majority of the price.While light-colored stones are widely available and affordable, large, deep, clear blue stones are rare, and the price can vary several times over even for the same carat weight. Let's look at them in order.
① Color | The darker and purer the blue, the higher the rating
Color is most important with aquamarine. The reason is that while highly transparent stones are produced in relatively large quantities, dark-colored stones are produced in limited quantities, and the rarity of the color directly creates a price difference. GIA states that the most valued color for aquamarine is ``dark, slightly greenish blue to pure blue.'' Most of the stones on the market are pale pastel blue, and the darker the color, the higher the value, while stones that are too green or grayish tend to be valued lower.
In actual appraisals, determining the darkness of the color has the biggest impact on the appraised value. For light-colored small stones, the focus is on the jewelry design and metal value, while for dark-colored stones, the ``stone price'' is evaluated on a per-stone basis. We check colors in both near-natural light and standard light sources, as lighting can make colors appear darker. Furthermore, regarding the aquamarines we sell, SELBY strives to only handle stones with a certain color or higher. This is because we believe that color is a factor that affects satisfaction after purchase and evaluation in the second-hand market.
② Transparency | “Eye clean” is standard
According to the clarity classification of gemstones, aquamarine is usually classified as Type I, which is a gemstone with few inclusions that are noticeable to the naked eye. Therefore, in the market, the standard evaluation line is ``Eye Clean,'' in which no noticeable inclusions are visible to the naked eye, and stones with inclusions or cloudiness that are visible to the naked eye tend to receive significantly lower evaluations. This is a big difference from emerald, which tends to retain its value even with inclusions.
③ Carat｜Large grains are not uncommon, but “dark-colored large grains” are exceptional
Aquamarine is easy to produce large crystals, and loose crystals of over 10 carats can also be seen on the market. Therefore, it is not as simple as "bigger = more expensive", and the unit price per ct is more closely related to color than size. However, the thicker the crystal, the darker the color tends to appear, so stones that have been cut into small pieces while maintaining their dark color, and large, dark-colored stones are highly valued for their rarity.
④ Cut | Is the color brought out to the maximum?
Aquamarine is often cut deeply to make pale colors appear darker, and emerald cuts (square step cuts) and oval cuts are standard. Stones with large windows (the phenomenon in which the center of the stone appears to be missing) or stones with distorted proportions may be evaluated based on recutting (repolishing).
⑤ Processing: Heating is common and is thought to have little effect on value.
Many of the aquamarines on the market are said to have been heat-treated to remove the yellow tinge and stabilize the blue color. Heating is a permanent treatment that is widely accepted in the industry and is considered to have a small impact on value if disclosed. On the other hand, it has been reported that "Maschiche type beryl", which has a deep blue color derived from radiation exposure, fades due to light and heat, and is distinguished from ordinary aquamarine, and its value is also significantly different.
| Evaluation criteria | Conditions for high evaluation | Impact on value |
|---|---|---|
| color | Deep, pure and bright blue. No grayish or excessive greenishness | very large (most important) |
| transparency | Inclusions cannot be seen with the naked eye (eye clean) | big |
| carat | Large grains that maintain their dark color are rare. | great in combination with color |
| cut | Well-proportioned proportions that bring out the colors | medium |
| processing | General heating is acceptable. Irradiation systems with a risk of color fading are evaluated separately from regular products. | Heating is small/irradiation system is large |
What is the highest peak “Santa Maria Color”?
Santa Maria color is a distribution name that refers to a deep, vivid blue color with little greenishness, which is particularly highly regarded among aquamarines.The name comes from the Santa Maria de Itabira mine in Minas Gerais, Brazil, and today it is generally used as a color grade for ``dark blue that has reached that standard'' regardless of where it is produced. A similar color from Mozambique is sometimes called Santa Maria Africana.
It should be noted that there is no internationally unified color standard for Santa Maria colors. In Japan, identification organizations such as the Central Gem Laboratory (CGL) sometimes add comments such as ``It is called Santa Maria aquamarine color'' to the identification report for aquamarines that meet certain color standards. These comments are statements of opinion regarding color, and operations and judgments may vary depending on the institution.
In the second-hand market, it is not uncommon for the purchase and sale prices to differ by several times between a Santa Maria color with comments from an identification organization and a light-colored aquamarine of the same size. On the other hand, we also see cases where the word "Santa Maria" is only advertised verbally or on tags, and there is no identification document to back it up. At SELBY, we evaluate products based on the actual color and the contents of the identification report, not the name.
Relationship between production area and value
Aquamarine is a gemstone whose price is determined by the quality of the stone itself rather than the place of origin.Unlike rubies and sapphires, the name of the place of origin itself rarely commands a large premium, and if the quality is the same, the price difference depending on the place of origin is said to be limited. However, colors from Brazil, especially those from the Santa Maria mine, have historically had exceptional brand power.
| Production area | Features |
|---|---|
| Brazil (Minas Gerais, etc.) | Historical major production area. Known for the production of high-quality dark stone, including the Santa Maria mine. |
| mozambique | Produces dark-colored, high-quality stone. Known as "Santa Maria Africana" |
| madagascar | One of the important production areas that produces high-quality blue stones |
| nigeria | Considered to be a stable source of mainly medium to small grains. |
| Pakistan/Afghanistan | Known for its highly transparent crystals, it is also popular as a mineral specimen. |
| Vietnam, China, etc. | Considered to be a source of commercial quality mainly for light colors. |
Please note that general identification documents do not specify the origin of aquamarine. It is important to understand that tags that indicate the country of origin and verbal explanations are only declarations made by the seller.
How to distinguish between similar stones and fakes
Aquamarine is most commonly confused with blue topaz, followed by synthetic spinel and colored glass.In particular, while blue topaz is very similar in color, its retail price is significantly lower than aquamarine, so if you buy or sell it without being able to tell the difference, you may incur a loss. For reliable identification, inspection by a gem identification organization is required.
| Item | aquamarine | blue topaz | Synthetic spinel/glass |
|---|---|---|---|
| true identity | natural beryl | Natural topaz (mostly colored by irradiation + heating) | artificial material |
| refractive index | Approximately 1.577~1.583 | Approximately 1.61~1.64 | Depends on material |
| specific gravity | Approximately 2.68 to 2.74 (light) | Around 3.5 (heavy) | Depends on material |
| color trends | Soft blue. Dichroism (blue to almost colorless in viewing direction) | Often bright and uniform blue | often unnaturally uniform |
| market value | Wide range of quality | Significantly cheaper than aquamarine | It has almost no asset value as a jewel. |
In the actual assessment, we use a combination of tests such as the ``feeling of weight when held in the hand'' based on the difference in specific gravity, the presence or absence of dichroism, and the measurement of refractometers and specific gravity. In vintage jewelry, there are actually cases where a stone that has been passed down as aquamarine turns out to be blue topaz or synthetic spinel after testing. We recommend that you do not judge inherited items or old jewelry based on assumptions and instead send them in for identification.
Attention:Products with descriptions such as "aquamarine color" or "~style" may be made of materials that are not aquamarine. For official confirmation of the gemstone name, please check the "Mineral Name/Gemstone Name" column on the identification report.
Actual evaluation and appraisal in the used market
The basic structure of aquamarine in the second-hand market is that ``light colors and small stones are evaluated based on the base metal and design,'' and ``dark colors and large stones are evaluated for the stone itself.''This is because the price difference depending on quality is more severe than in the new market, and the appraised value of the same "aquamarine ring" can vary greatly.
The main points that affect the assessed value are as follows.
- Color intensity:The most influential factor. Dark-colored stones are evaluated in units of one stone.
- Whether or not there is a certificate of identification:In particular, the Santa Maria color identification book with comments is important as support for the evaluation.
- Bullion:Bullion market prices such as platinum and K18 are the basis for appraised value.
- Brand:High jewelry brand products have added brand value.
- Condition:Chips and strong scratches are a minus. However, there are cases where the value can be restored by recutting.
According to SELBY's sales results, demand for aquamarine tends to increase in early spring, and there are also characteristics of demand such as ``light-colored but highly transparent stones sell well depending on the design.'' Additionally, as it is the birthstone for March, demand for gifts supports both appraisal and sales. We believe that the strength of specialty stores that handle sales themselves is that they can set purchase prices that include sales expectations.
Points to note when purchasing
When purchasing aquamarine, the two most important points are ``don't judge the color just by looking at the light'' and ``check the gem name on the identification book.''Even pale stones can appear dark under store lighting, and the impression can change dramatically when viewed under natural light. Please refer to the checklist below.
- Have you checked the color in natural or similar lighting?
- Can you confirm that it is “natural beryl (aquamarine)” in the identification book?
- If you are singing "Santa Maria", is there any evidence such as comments from an identification organization?
- Are there any inclusions or cloudiness that are visible to the naked eye (eye clean)?
- Isn't the "window" that allows the center of the stone to be seen through too large?
- Is the price commensurate with the quality? (Are the prices of dark-colored stones attached to light-colored stones?)
One point:Aquamarine is durable with a hardness of 7.5 to 8, but care must be taken to prevent it from chipping due to strong impacts and sudden changes in temperature. While regular stones often tolerate ultrasonic cleaning, it may be recommended to avoid it for stones with inclusions or cracks. For daily care, use neutral detergent, lukewarm water, and a soft brush.
Points that are highly valued when selling
If you want to sell your aquamarine, the two things that will make a big difference are ``getting a certificate of authenticity'' and ``asking a specialty store that can evaluate gemstones.''This is because purchasing stores that only look at the bullion price may not reflect the value of dark colored stones or Santa Maria colored stones in their appraisals.
- Gather documents and accessories at the time of purchase, such as a certificate of authenticity:In particular, the Santa Maria color identification book with comments is the basis for evaluation. Even if you have lost the stone, a specialty store can evaluate the stone itself.
- Choose a store where you can evaluate colored stones:The more a store has a sales channel for colored stones, the easier it is to reflect the value of the stone in the purchase price.
- Remove light dirt:If the stone is cloudy due to sebum or dust, it will be difficult to convey its true color and clarity.
- Consult on multiple points at once:By evaluating multiple pieces of jewelry at the same time, it is easier to receive comprehensive proposals from both base metal and stone perspectives.
In actual appraisals, there were cases in which a dark aquamarine, which is difficult to obtain today, was found in an old ring inherited from a grandmother. Even if the design is old, the value of the stone, platinum, and gold will not be lost. It is worth having the jewelry you are unsure about disposing of get it appraised by a specialty store.
Frequently asked questions (FAQ)
Q1. What determines the value of aquamarine?
It is determined by five factors: color, transparency, carat, cut, and processing, of which ``color intensity and purity'' are the most important. The deeper and clearer the blue, the rarer it is, and the price can be several times higher than a light-colored stone even for the same size. The standard transparency is ``eye clean'', meaning that no inclusions are visible to the naked eye.
Q2. What is Santa Maria Color?
It is a distribution name that refers to the deep, vivid, and less greenish blue color that is particularly highly valued among aquamarines, and it originates from the Santa Maria de Itabira mine in Brazil. Although there are no internationally unified color standards, in Japan, identification organizations such as the Central Gem Laboratory (CGL) sometimes add comments to stones that meet the standards.
Q3. What is the difference between aquamarine and blue topaz?
Aquamarine is made from beryl, and blue topaz is made from topaz, which are different minerals and have different refractive indexes and specific gravity. Although the colors are similar, blue topaz is often colored by irradiation, and its retail price is significantly lower than aquamarine. For reliable identification, inspection by an identification organization is required.
Q4. Is aquamarine heat treated?
Many of the aquamarines on the market are said to have been heat-treated to remove the yellow tinge and stabilize the blue color. Heating is a permanent treatment that is widely accepted in the industry and is considered to have a small impact on value if disclosed.
Q5. Does aquamarine have any asset value?
It depends on the quality. The common light-colored aquamarine is widely distributed, and its value is primarily as a decorative item rather than an investment asset. On the other hand, high-quality dark-colored stones and Santa Maria color stones are rare and may be highly valued on the second-hand market, and the stones themselves have an appraised value.
Q6. Can I sell light colored aquamarine?
It is possible to sell. However, in the case of light-colored small grains, the appraised value tends to be centered around the value of the metal such as platinum or K18 and the design. Jewelry with high transparency and design is in demand even in the second-hand market.
Q7. Can you do an appraisal even if I don't have a certificate of authenticity?
It's possible. At specialty stores, the stone itself can be evaluated using tests such as a refractometer or specific gravity measurement. However, if you have documents to support your evaluation, such as a Santa Maria color identification book with comments, the evaluation will go smoothly and you will be more likely to receive a high evaluation.
Q8. Will aquamarine fade?
The blue color of normal aquamarine is stable and there is almost no fear of fading with daily use. However, it has been reported that "Maschiche type beryl", which has a deep blue color derived from radiation exposure, fades due to light and heat, and is distinguished from normal aquamarine.
Q9. Does the value of aquamarine change depending on where it is produced?
Basically, the quality of the stone itself determines the price rather than the place of origin. However, the dark blue that comes from the Santa Maria mine in Brazil has exceptional brand power. Please note that general identification documents do not specify the origin of aquamarine.
Q10. Are aquamarine and emerald the same mineral?
Both are from the same mineral group, beryl. Aquamarine is a blue color created by trace amounts of iron, and emerald is a green color created by chromium or vanadium. Aquamarine crystals with fewer inclusions are easier to obtain, and transparency standards are also stricter.
Q11. How to care for aquamarine?
It is safe to wash with lukewarm water containing a neutral detergent and a soft brush. It is durable with a hardness of 7.5 to 8, but please avoid strong impacts and sudden temperature changes. While regular stones often tolerate ultrasonic cleaning, it may be recommended to avoid it for stones with inclusions or cracks.
Q12. What if I want to know the value of the aquamarine I inherited?
We recommend that you first check whether the stone is genuine and the value of the stone and metal through a free appraisal at a specialty store. While similar stones may be used in older jewelry, you may also find dark-colored stones that are difficult to obtain today. You can decide whether to sell or not after the appraisal.
Summary｜The value of aquamarine is determined by its “color”
We will summarize the points for evaluating the value of aquamarine.
- The center of value isintensity and purity of color. The darker and clearer the blue, the rarer and highly valued it is.
- The highest peak issanta maria color. However, there is no unified standard, and comments from identification organizations are the basis for this.
- The standard transparency is eye-clean. The effect of general heat treatment on value is said to be small.
- Be careful not to confuse it with similar stones such as blue topaz. Differentiation is required for accurate identification
- In the second-hand market, light-colored small stones are mainly valued for their bare metal, while dark-colored large stones are valued for their stones themselves.
If you are concerned about the value of your aquamarine, we recommend having it appraised at a store that specializes in colored stones. At SELBY, we conduct a grounded evaluation of each item based on both gemological inspection and second-hand market sales data.
Related articles
- Difference between aquamarine and blue topaz | Explaining how to tell them apart and the price difference (internal link planned)
- What is Santa Maria Aquamarine? Standards, differentiation certificate, market price (internal link planned)
- Emerald value evaluation | Evaluation criteria for beryl gemstones (internal link planned)
- Purchase price of colored stones and tips for selling them at a high price (planned internal link)
- Difference between gemstone identification report and appraisal certificate | Role in appraisal (internal link planned)
Reference materials
- GIA (Gemological Institute of America) "Aquamarine Description / Aquamarine Quality Factors"
- Gem-A (Gemological Institute of Great Britain) Public information on beryl
- Handbook of Mineralogy “Beryl”
- Mindat.org “Aquamarine (Beryl)”
- ICA (International Colored Stone Association) "Aquamarine"
- Public information regarding Central Gem Laboratory (CGL) identification report comments
- Selby Co., Ltd. appraisal/sales practice data