Why are rare stones expensive?
A jewelry buyer explains the reasons for determining the value of rare stones and the market value of the Japanese yen.
Factors that determine prices, the market price of the Japanese yen (0.5 to 2ct), distribution structures that other sites do not touch, and how to choose according to purpose. In order to make your judgment based on this article, we have summarized the primary information on gemology and SELBY's appraisal practices.
SUPERVISED BY
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.
Conclusion of this article
Rare stones become expensive only when the three factors of "production volume", "beauty", and "demand" are met. It's not expensive because it's rare, butIt's expensive because it's a rare stone that many people want.——This is the most important perspective when understanding prices. Even if there is only one mineral in the world, if there is no demand, there will be no market price, and on the other hand, the price of a popular rare stone will rise as the supply decreases.
Summary in 30 seconds
- The basis for this height is ``absolutely low output.''It only occurs under specific geological conditions, and the quality of rough stone that can be used for jewelry is even more limited.
- Prices are not determined solely by rarity;Color, durability, production area, demand, distribution costis determined by a combination of
- in colored stonesColor is about 60% of value, thenApproximately 15% is produced in(GIA).
- Prices for stones that are too rare take into account the risk of unsold items.This creates a price difference that cannot be explained by scarcity alone (SELBY practice).
- in the second hand marketIdentification certificate/processing disclosure/resale demandgreatly influences the buying and selling price. “Verifiable information” protects value.
01What is rare stone?
Rare stones are a general term for rare gemstones that are produced in extremely small quantities and are only available in the market. It is not a technical term with a clear international definition, but is a name commonly used in the jewelry industry and collectors' market. In contrast to common gemstones such as diamonds, rubies, sapphires, and emeralds, this term often refers to ``stones that are found in small amounts'' such as paraiba tourmaline, alexandrite, grandidierite, and paynite.
The conditions for being a “jewel” have been established since ancient times.Beauty, Rarity, DurabilityIt has been said that there are three. Rare stones are easier to understand if you understand them as a group of stones that are particularly rare.
Figure 1｜Three conditions for gemstones and the position of rare stones
In the field of distribution, the term "rare stone" is used to refer to both (1) stones that are mineralogically produced in very low quantities, and (2) stones that have recently become difficult to obtain due to depletion of production areas. As a buyer, it is important not to confuse the two.
02Why are rare stones expensive? 6 reasons to decide the price
The reason rare stones are so high is that they only occur under limited geological conditions, and there are very few gemstones of quality that can be used for jewelry. However, scarcity is only the "foundation" of price. Actual price is determined by a combination of six factors:
Figure 2 | Six reasons why prices are piling up
2-1. Low production | Hardly any on earth to begin with
Rare stones are rare because the combination of elements that make them up, as well as the temperature and pressure conditions necessary for their formation, can only be found in very limited places on Earth. Paynite, a typical example, is said to be the only mineral that simultaneously contains the two elements boron and zirconium, and the rarity of this combination is explained as the reason for its extreme rarity. As of 2005, it was recorded in the Guinness Book of World Records as the "world's rarest gem mineral," and at that time only a few dozen specimens were known to be cut.
Figure 3｜How a gemstone is born (generation process)
In actual appraisals, "low production volume" and "low quantity on the market" are treated as separate issues. Even if you have rough stones, the price of stones that are transparent, have few scratches, and can withstand cutting, and is difficult to obtain, will be more expensive than the amount produced.
2-2. Beauty | Color is about 60% of the value of colored stones
Color is the most important factor in the value of colored gemstones, and experts estimate that it accounts for approximately 60% of the value. The industry evaluation model introduced by GIA explains that color has an impact of about 60%, region of origin has an impact of about 15%, and cut and size each have an impact of about 10%. Colors are evaluated based on three elements: hue, tone, and saturation, and the more vivid and deep the color, the higher the evaluation.
Like Paraiba tourmaline's "neon blue" derived from copper and alexandrite's "day and night" color change, having colors that cannot be reproduced with other stones greatly pushes up the price of rare stones.
Figure 4 | Breakdown of value factors for colored stones (GIA model guideline)
Even in the used market, the color has the biggest impact on the price for the same type of stone. It is not uncommon for a slight difference in color saturation to result in a price difference of several times. Photos do not accurately convey color, so physical verification and reliable identification are especially important.
2-3. Durability | Can it be used as jewelry?
Stones with low durability have limited value as jewelry, no matter how rare they are. Durability is evaluated using three criteria: hardness (Mohs hardness = resistance to scratches), toughness (resistance to cracking and chipping), and stability (resistance to heat, light, and chemicals). Alexandrite has a Mohs hardness of 8.5, and spinel has a hardness of 8, making it durable for everyday use, which underpins its high practical value.
On the other hand, stones that are rare but have low hardness or strong cleavage (the tendency to break in a certain direction) are considered more suitable for pendants and collectibles than rings, and tend to have a lower reputation in the jewelry market.
When making an appraisal, we always consider ``how the stone will be used.'' Rare stones with low hardness may be popular with collectors, but demand for resale as daily wear jewelry is low, making it difficult to price them.
2-4. Production area/supply | "Where was it harvested" and "Cannot be harvested anymore"
Even if the quality is the same, the place of origin greatly influences the value, and the depletion of mines will push up the price even more. It has been reported that sapphires from Kashmir, emeralds from Colombia, and rubies from Myanmar (Burma) command a higher "origin premium" than other regions because of the colors that can only be found in those regions and because the ore veins are nearly exhausted. The place of origin is considered to be the second most important factor in determining value after color.
Stones such as Paraiba tourmaline and alexandrite, whose original major deposits have been nearly exhausted, become rarer and more expensive as new supply dwindles.
In order to reflect the origin premium in the price, certification of origin from a reliable identification organization such as GIA, Gübelin, or SSEF is a prerequisite. At the distribution site, "self-proclaimed/rare production areas" without any evidence of the production area are considered weak as a basis for pricing.
2-5. Demand｜If it is not known, it will not increase
Rarity changes into price only when there is a demand for the stone. Even for stones that are produced in small quantities around the world, if public awareness is low, demand may be weak and prices may remain surprisingly affordable. On the other hand, if the media or a famous jeweler adopts the item, or if the item attracts attention from collectors or investors, the lack of supply will be reflected in the price all at once.
This is why the prices of stones that are both well-known and rare, such as Paraiba and Alexandrite, increase.Scarcity and market price do not necessarily match.
In the second-hand market, whether or not it can be resold is a serious consideration. Rare stones that are not popular or recognized tend to have an asymmetry in which they are expensive to buy and difficult to find buyers to sell. Before purchasing, it is important to consider whether there will be someone who will want this stone in the future in order to protect its value.
2-6. Distribution structure | Selling costs also add to the price of rare gemstones
For rare stones, the selling price may be affected not only by the value of the stone itself, but also by the ``cost to sell''. Unlike regular jewelry, there are only a limited number of buyers, so it is not uncommon for jewelry to remain in stock for a long period of time from purchase to sale. There is a structure in which this inventory risk and sales costs are added to the price.
Figure 5 | Process for determining prices (cost price = not market price)
Loose rare stones are often purchased in bulk from mines or overseas dealers. However, not all of them sell at the same speed, and some stones remain in stock for several years. In fact, there have been cases where some of the items we purchased in bulk from overseas dealers were able to be sold immediately, but the rest remained in stock for a long time.
For this reason, some loose dealers, when purchasing 10 stones at once, allocate more of the purchasing and storage costs to the 2 to 3 stones that are in relatively high demand and can be sold quickly, and set prices for the remaining stones at prices that are easier to sell.
This kind of pricing is one way of thinking about distribution that takes into account the inventory risk unique to rare stones, and as a result,The reason why there is a large price difference depending on the store even for the same quality and type of stoneIt has become one of the.
Furthermore,At SELBY, we comprehensively evaluate the quality, rarity, demand, and market price of each stone, and determine the price based on the value of each stone.
03What determines the price of jewelry? ｜Breakdown of value factors (GIA)
The price of colored gemstones is determined by factors such as color, production area, cut, size, clarity, etc. In the industry evaluation model introduced by GIA, the influence of each element is roughly organized as follows (varies depending on the stone type).
| value factor | Approximate impact level | points |
|---|---|---|
| color | Approximately 60% | Evaluated by hue, brightness, and saturation. most important |
| Production area (origin) | Approximately 15% (large fluctuation) | Sapphires from Kashmir are particularly expensive. |
| cut | Approximately 10% | Left and right reflection and shine of light |
| Size (carat) | Approximately 10% | Larger stones tend to be rarer and more expensive. |
| Shape, transparency, etc. | rest | "Allowable inclusions" differ for each stone type. |
*This is a guideline for the one-rating model introduced by GIA, and the actual ratio will vary depending on the stone type, quality, and market.
Clarity differs greatly depending on the type of stone. Emeralds naturally have inclusions, and are highly valued because they are exceptionally "eye-clean" (inclusions cannot be seen with the naked eye). Diamonds, on the other hand, are nearly flawless, making them rarer and more expensive.“Higher clarity does not necessarily mean higher quality”This is the point where beginners are most likely to misunderstand.
04Representative rare stones and rarity [comparison table]
Even with the same "rare stone", the reason for its rarity and price range are very different. Below is a comparison table of representative rare stones arranged based on primary information.
| Gem name | mohs hardness | Main production areas | Reasons and characteristics of scarcity |
|---|---|---|---|
| paraiba tourmaline | Approximately 7-7.5 | Brazil, Mozambique, etc. | Neon blue/green derived from copper. Popular as raw ore deposits are depleted |
| alexandrite | 8.5 | Russia, Brazil, Sri Lanka etc. | Color change that changes color during day and night. Good quality ore deposits are depleted |
| pay night | 8 | myanmar | The only mineral containing boron and zirconium. Once the world's rarest |
| Taaffeite | Approximately 8-8.5 | Sri Lanka, Tanzania, etc. | The first gemstone discovered as a cut stone. Very small sample size |
| red beryl | Approximately 7.5-8 | Utah, USA | Production areas are extremely limited, and large grains are almost non-existent. |
| Grandidierite | Approximately 7-7.5 | madagascar etc. | Jewelry grade clear gemstones are extremely rare. blue-green pleochroism |
| tanzanite | Approximately 6-6.5 | Tanzania (1 location) | Only one production area in the world. Hardness is low |
The mineral ``kyawthuite'', which is the only one found in the world, was approved by the International Mineralogical Association (IMA) in 2015, and the specimen is kept at the Natural History Museum of Los Angeles. However, thisThis is an academic specimen and is not a stone distributed in the jewelry market.This is a good example of how "rare = expensive" does not necessarily hold true.
05Market price of rare stones [Japanese yen/0.5ct~2ct]
The market price of rare stones can vary several times depending on the color, place of origin, and treatment, even for the same type of stone, so it is practical to understand them in terms of their "width." The following is a reference range based on SELBY's appraisal and sales experience (jewelry grade/loose guideline).
| Stone type | 0.5ct | 1ct | 2ct |
|---|---|---|---|
| paraiba tourmaline | Approximately 800,000 to 2,000,000 yen | Approximately 2 million to 6 million yen | More than 5 million yen |
| alexandrite | Approximately 500,000 to 1,500,000 yen | Approximately 1.5 million to 5 million yen | Over 10 million yen depending on quality |
| Taaffeite | Approximately 200,000 to 1 million yen | Approximately 1 million to 4 million yen | Individual evaluation due to low distribution |
| pay night | Individual evaluation | Individual evaluation | Highly representative, please inquire |
| Grandidierite | Individual evaluation | Individual evaluation | Clear stones are rare and individually evaluated |
*Price varies greatly depending on quality, color, production area, and processing. This is a reference market price for SELBY and does not guarantee the actual price or assessed value.
Figure 6｜1ct reference price range of major rare stones (10,000 yen)
Even for the same "1ct Paraiba", the price will be several times different between a stone with a neon blue color and a certificate of origin, and a stone with a lighter color. The numbers in the tables and figures are just a starting point, and the final judgment will be made based on the actual item and the identification details.
06From the SELBY assessment site | How is it actually evaluated?
At SELBY, when appraising rare stones, we first check the identification details and then evaluate by integrating multiple market information. Specifically, the judgment will be based on the following four axes.
- Current domestic distribution volume(How active is it in the Japanese market now?)
- Overseas auction price(Backing up the global situation)
- Past sales results(How much did it actually sell for?)
- Used market demand(Is the stone easy to find a buyer?)
If even one of these is missing, we will be cautious in our evaluation. Rare stones in particular have few "recent transactions that can be referenced", so we check the validity of the price by comparing multiple sources.
Figure 7｜2025-2026 Rare stones with increased number of appraisal and purchase inquiries
From 2025 to 2026, we are receiving an increasing number of requests for appraisal and purchase of rare stones.Paraiba tourmaline, alexandrite, carletonite, bicolor sapphireIt was. Inquiries are expanding to stones like carletonite, which until now had little public recognition, and we can see in the field how ``being known'' drives demand and prices. (Trends change depending on the market environment)
07Real rare stone second hand market
The biggest feature of the used market for rare stones is that it is a "thin market" with few transactions. Since there are a limited number of buyers and sellers, even the slightest imbalance in supply and demand can cause large price fluctuations. While resale demand for popular stone types (Paraiba, Alexandrite, etc.) is relatively stable, there are cases where it is difficult to find people who want them for rare stones that are less well known.
Main factors that affect prices in the used market
- Presence or absence of a certificate of identification and issuing agency:The strength of the basis for the price changes depending on whether there is identification or origin certification from a reliable institution.
- Treatment disclosure: The presence or absence of heating, impregnation, diffusion treatments, etc. and disclosure are directly linked to value and resaleability.
- Resale demand (popular):If a stone is rare but has low demand, it will be difficult to find a buyer when selling it.
- Balance between size and quality: Rare stones have extremely few large stones, so high-quality large stones command a premium.
In the distribution field, rare stones tend to have a larger difference (spread) between the "buy price" and "sell price" than ordinary gemstones. This is because the market is thin and inventory risk is high (→ 2-6 Distribution Structure). If you are purchasing with the intention of selling, the surest way to protect the future appraised value is to keep identification and processing information at the time of purchase.
08Points to note when buying rare stones | Fake, imitation, and processing
The rarer the stone, the more important it is to check whether it is genuine and whether it has been processed. Because it is rare and expensive, it is easy for imitations, similar stones, and excessively processed stones to be mixed in. Please be sure to check the following points before purchasing.
- Is there a reliable certificate of identification?: Are the stone type name, weight, and whether or not it has been treated clearly stated?
- Is it being mistaken for a similar stone?: Taaffeite was once confused with spinel and was first discovered as a cut stone. It is not uncommon for stones to look similar.
- Is it a synthetic stone or artificial stone?: There are also stone types that can be reproduced in a laboratory. The value varies greatly depending on whether it is natural or synthetic.
- Processing details and disclosure: Heating, impregnation, etc. are not a problem if they are disclosed, but they are information that should be reflected in the price.
- Evidence of production area: If you claim a premium on the country of origin, is there a certificate of origin from a reliable organization?
From the perspective of a jewelry store, we always question the reason for a rare stone that is too cheap. Prices that deviate significantly from the market price are often a sign of the wrong treatment, composition, or type of stone. Please be sure to leave the final determination of authenticity to a specialized institution.
09Points to note when selling or submitting rare stones for appraisal
The key to selling rare stones at a high price is to make sure that a third party can prove the value of the stone. In a thin market, buyers seek a discount to compensate for the risks they take on stones that lack information. Conversely, the more information you have to prove it, the more likely it will be evaluated at a fair price.
Things to prepare before the assessment
- Certificate of identification/authenticity(Certificate of origin if available)
- Information at the time of purchase(Record of purchase store, purchase price, and processing)
- accessories(Original box, warranty card, case)
- stone condition(Presence or absence of chips, scratches, and re-polishing history)
In the actual appraisal, we first determine the stone type, weight, and treatment using an identification document, then check the color, cut, and condition, and then comprehensively evaluate the stone based on domestic distribution volume, overseas auction prices, our own sales history, and second-hand demand. Appraisals can be made even if there are no documents, but since it takes time and cost to confirm authenticity and processing, evaluations tend to be cautious.
10Which rare stone should you choose? | Guide by purpose
“In the end, which one should I choose?” The most suitable rare stone will change depending on your purpose. When in doubt, consider the following criteria.
Paraiba/Alexandrite
Popularity and rarity coexist, and used demand is relatively stable. Easier to find a buyer when selling.
Peinite/Taaffeite/Grandidierite/Red Beryl/Carletonite
Output is extremely low, and ownership itself is valuable. However, keep in mind that the resale market is thin.
Alexandrite (Hardness 8.5) / Spinel (Hardness 8)
It has high hardness and is suitable for everyday jewelry. Spinel is relatively easy to obtain.
We recommend caution when purchasing stones with little recognition for investment purposes. This is because stones that are rare but have a limited number of buyers tend to have a large difference between the buying and selling prices. If you are conscious of its asset value, it is realistic to first consider stones that are popular, recognized, and durable.
11Frequently asked questions (FAQ)
What is rare stone?
It is a general term for rare gemstones that are produced in extremely small amounts and have a limited distribution in the market. It is not a technical term with a strict international definition, but is a name commonly used in the industry and collector market, with typical examples being Paraiba tourmaline and alexandrite.
Why are rare stones expensive?
This is because base stones can only be produced under specific geological conditions, and there are very few gemstones of quality that can be used for jewelry. The final price is then determined by a combination of color, durability, production area, demand, and distribution costs. Rarity alone does not make it expensive.
What is the rarest gemstone in the world?
Currently, only one specimen of kyawthuite has been discovered in the world, and it is known as a single specimen mineral. In 2015, it was approved as a new mineral by the International Mineralogical Association (IMA). However, it is an academic specimen and is not a stone distributed in the jewelry market.
If it's rare, will it always sell for a high price?
Not necessarily. A price is established only when there is demand. Rare stones with little recognition may be expensive when purchased, but it may be difficult to find a buyer when selling. When considering future resale potential, choosing a stone type that is popular and recognized is also a criterion.
How much is the market price of rare stones?
They vary greatly depending on the stone type and quality. According to SELBY's reference market price, Paraiba tourmaline is about 2 million to 6 million yen per ct, and alexandrite is about 1.5 to 5 million yen. In reality, each item will be evaluated individually, as it will vary several times depending on the color, origin, and whether or not it has been processed.
What is the most important value for colored gemstones?
It is color. According to the evaluation model introduced by GIA, color accounts for approximately 60% of a colored stone's value, and the more vivid the color with a good balance of hue, brightness, and saturation, the higher the value.
Why are the prices different depending on the store even though it is the same stone?
Rare stones have a limited number of buyers and tend to be in stock for a long time, so inventory risk and sales costs are reflected in the price. Due to this difference in distribution structure, there can be large price differences between stores even for the same stone type and quality.
Does the price change depending on the country of origin?
It will change. Sapphires from Kashmir, emeralds from Colombia, and rubies from Myanmar are reported to command high prices due to their unique colors and the depletion of the mineral deposits. However, in order to reflect this in the price, certification of the origin from a reliable institution is a prerequisite.
Are rare stones an investment?
The market is thin and the difference between buying and selling prices tends to be large, making it unsuitable for investments aiming for short-term gains in price. Selecting stones that are popular, durable, and distinguishable with the assumption of long-term ownership will lead to risk management. It is not a financial product and there is no price guarantee.
Should I not buy rare stones with low hardness?
It depends on the purpose. Even stones with low hardness can be used for pendants and collections. However, it may not be suitable for rings that are worn every day, and resale demand tends to decline. We recommend that you decide how you will use it before making your selection.
How can I spot fakes and imitations?
The best way to be sure is to check the certificate from a reliable identification agency. There are many stone types that look similar, and it can be difficult for even experts to distinguish them with the naked eye. An inexpensive stone that is far off the market price is a sign that you should suspect that the stone has been treated, synthesized, or of the wrong type.
Will treated stones be devalued?
It depends on the content of processing and disclosure status. Common and stable treatments such as heating are often acceptable in the market, while others such as impregnation and diffusion affect value. The important thing is whether the processing is "disclosed", and the biggest problem is that the processing is not disclosed and is bought and sold as if it were not processed.
Can I sell a stone without a certificate of identification?
It sells well, but because it takes time to verify authenticity and processing, people tend to evaluate it cautiously. If possible, it is more likely that the item will be appraised at a fair price if you have it authenticated by a reliable institution before the appraisal.
What rare stones will be popular in 2025-2026?
At SELBY's appraisal and purchase sites, inquiries about Paraiba tourmaline, alexandrite, carletonite, and bicolor sapphire are increasing. There is a tendency for the demand for a stone to increase as it becomes more widely recognized.
12Summary
The reason why rare stones are expensive isColor, durability, production area, demand, and distribution costs all add up based on the fact that the amount of production is "absolutely low."It is. Color accounts for about 60% of the value of colored stones, and the depletion of production areas and supply further pushes up prices. Furthermore, rare stones have a distribution structure that other gemstones do not have, where the "inventory risk" due to their rarity increases the price.
On the other hand, just as Kawazurite, which is the only one in the world, is an academic specimen in a museum,Rarity and market price do not necessarily match.Expensive rare stones are ``rare stones that many people want.'' Rare stones do not have value because they are rare, but value is created only when their rarity, beauty, demand, and resaleability are all present. At the appraisal site, we carefully assess each stone to see if it is truly a gemstone that will be valued in the market.
Whether buying or selling, the key to protecting value is "information that can be verified by a third party" - certificates of identification, disclosure of processing, and certificates of origin. If you are looking to choose a stone like Paraiba or Alexandrite if you are looking for wealth, payinite or taaffeite if you are looking for a collection, or a hard stone for everyday use, you will be able to choose a stone that you will not regret.
13Related articles
14Reference materials (primary information)
- GIA (Gemstone Institute of America) "Colored Gemstone Value Factors" (value factors of color, origin, cut, and size)
- GIA "4Cs" (Cut, Color, Clarity, Carat evaluation system)
- International Mineralogical Association (IMA) New Mineral Approval Record (kyawthuite, 2015)
- Natural History Museum of Los Angeles County/Caltech (kyawthuite specimens and descriptions)
- Guinness World Records (painite: Former record of "the world's rarest gemstone mineral")
- Mindat.org/Handbook of Mineralogy (hardness, chemical composition, and locality data for each mineral)
- Selby Co., Ltd. Appraisal/Sales/Purchase Practice (Primary Information)