November 20, 2023
Heated vs. Unheated Sapphire

Heated vs. Unheated Sapphire: A Comprehensive Guide for Jewellers and Gemstone Enthusiasts

Sapphires have captivated the hearts of jewelers and gemstone enthusiasts for centuries. However, not all sapphires are created equal. A fundamental distinction exists: heated vs unheated sapphires. Did you know that approximately 98-99% of sapphires on the market undergo some form of heat treatment? Understanding the differences between heated and unheated sapphires is crucial for grasping the true value of your purchase, especially given that the naked eye cannot tell these differences.

In this comprehensive guide, we will delve into the nuances of heated vs unheated sapphires, exploring how to identify them and determining the best option for both jewelers and gemstone enthusiasts alike.

What is a heated sapphire?

Heated sapphires are gemstones that have undergone a process of controlled thermal treatment to enhance their color and clarity. This treatment involves subjecting the sapphires to high temperatures, the heat helps to improve the gem's appearance by reducing or eliminating visible inclusions, intensifying the color saturation, and creating a more desirable overall aesthetic.

How is a sapphire heated?

Sapphires are heated using high-temperature furnaces or other heating methods. The gems are carefully heated to specific temperatures, which can range from a few hundred to over a thousand degrees Celsius, depending on the desired outcome. The heating process can take hours or even days, allowing the gem to gradually reach its optimal appearance.

What are the benefits of heated sapphires?

• Enhanced color: Heating sapphires intensify and improve the saturation of their hue, resulting in a more visually appealing gemstone.

• Improved clarity: Heat treatment can minimize or eliminate visible inclusions in sapphires, enhancing their clarity and overall beauty.

• More affordable: Heated sapphires are generally less expensive compared to  unheated sapphires.

What are the drawbacks of heated sapphires?

• Fading over time: The enhancement can fade or diminish over time, if exposed to high heat or secondary treatments, potentially impacting the gem's visual appeal and value.

• Altered natural integrity: Some purists argue that heating sapphires alter their natural integrity, potentially affecting their value and desirability among collectors and enthusiasts.

What is unheated sapphire?

Unheated sapphires, also known as natural or untreated sapphires, are gemstones that have not undergone any artificial heating processes. These sapphires retain their natural state as they were formed within the Earth.

What are the benefits of unheated sapphires?

• Authenticity and rarity: Unheated sapphires retain their natural color and character, appealing to collectors and gemstone enthusiasts who value their authentic, untreated state.

What are the drawbacks of unheated sapphires?

• Color variations: Unheated sapphires can exhibit variations in color, which may be seen as imperfections by some.

• Higher cost: Unheated sapphires are often more expensive than heated sapphires due to their rarity and limited supply in the market.

Differences between heated and unheated sapphires

Here are a few common differences between heated and unheated sapphires that you can look for when deciding between the two.

Aspect Heated Sapphire Unheated Sapphire
Price Typically lower Typically higher
Color Enhanced Natural
Durability Unaffected Unaffected
Rarity More common More rare

How to determine if a sapphire is heated or unheated

Heated Sapphire and Diamond Bracelet
Heated Sapphire and Diamond Bracelet

Identifying whether a sapphire has been heated or is unheated can be challenging, but there are several methods and indicators that can help determine the treatment status of the gemstone.

1. Inclusion patterns

One way to assess whether a sapphire has been heated is by examining its inclusion patterns. Heated sapphires often exhibit characteristic inclusion patterns caused by the heating process. These patterns may include missing or interrupted growth features, such as rutile needles, which are specific features created by the treatment.

In contrast, unheated sapphires may display natural inclusion patterns without these specific features. By carefully examining the inclusions within the gem, jewelers and gemstone enthusiasts can gain insights into the treatment history of the sapphire.

2. Color consistency

Another clue to identifying heated versus unheated sapphires is by observing the color consistency. Heat-treated sapphires tend to have more uniform and saturated colors. The heating process can enhance and intensify the color of the gem, resulting in a more consistent appearance throughout the stone. 

On the other hand, unheated sapphires may exhibit variations and unique color characteristics. These variations can be due to the natural growth and formation processes without any artificial treatments. Comparing the color distribution and consistency can provide valuable information about the sapphire's treatment status.

3. Gemological laboratories

Reputable gemological laboratories play a crucial role in identifying heated vs unheated sapphires. These laboratories employ advanced testing techniques and equipment to analyze gemstones accurately. Gemologists at these labs can conduct various tests, including microscopic examination, spectroscopy, and other scientific methods, to determine if a sapphire has been heated. They provide professional testing services and issue certificates that document the gem's treatment status. These gemological certificates are valuable for buyers and sellers as they provide an independent assessment and ensure transparency in the market. 

When purchasing sapphires, it is advisable to request a gemological certificate from a trusted lab to validate the treatment status of the gemstone.

4. Disclosing treatment information (if you’re a seller)

This is crucial when selling sapphires to maintain transparency and ensure that buyers can make informed decisions. Sellers should provide accurate information about whether a sapphire has undergone heat treatment or is unheated. Gemological certificates from reputable labs serve as important documentation of a sapphire's treatment status. Buyers can refer to these certificates to understand the gem's history and make well-informed purchasing choices. By prioritizing transparency and disclosure, the industry can foster trust and confidence among buyers and sellers of sapphires. 

At Ceylons Munich, we uphold stringent ethical standards, ensuring treatment information is revealed before any purchase is made. Our webshop explicitly mentions treatment information for each gemstone sold. 

Learn More about Heat Treatment of Sapphires here.

Which one should you choose?

When deciding between heated and unheated sapphires, there are several factors to consider:

• Budget: Heated sapphires are generally more affordable than unheated ones due to their abundance and the availability of treated gemstones. Unheated sapphires, although pricier, are considered more valuable by collectors and gem enthusiasts due to their authenticity and rarity.

• Purpose: Consider the intended use of the sapphire. If it is for personal enjoyment or everyday wear, heated sapphires can offer a cost-effective choice. The color enhancement achieved through heating can result in visually appealing gems suitable for regular use. On the other hand, if the gemstone is intended for investment purposes or as a valuable addition to a collection, unheated sapphires may hold greater long-term value. Their rarity and natural integrity make them highly sought after by collectors and enthusiasts.

• Seller reputation: It is crucial to consider the seller's reputation when purchasing sapphires. A reputable seller will provide accurate information about the sapphires and have a trustworthy track record. They will disclose whether a sapphire has been heated or is unheated and offer transparency throughout the buying process. By choosing a reliable seller, you can have confidence in the quality and authenticity of the sapphire you are purchasing. At Ceylons Munich, we prioritize transparency, keeping our customers informed about any treatments and adhering to stringent ethical standards. We have been serving jewelers in Europe and the US for almost a decade and are trusted by 300+ businesses.

• Personal preference: Ultimately, personal taste and aesthetic preferences should guide your decision. Some individuals value the enhanced color and affordability of heated sapphires. The vibrant, uniform colors achieved through heating can be visually appealing to many. However, others appreciate the authenticity and uniqueness of unheated sapphires. These gems retain their natural color and character, appealing to those who value untreated gemstones.

Therefore, when choosing between heated and unheated sapphires, consider your budget, purpose, and personal preferences. If you seek stunning hues within your budget, heated sapphires may be your go-to. Alternatively, for those seeking rare and one-of-a-kind gems, unheated sapphires hold unparalleled allure.

At Ceylons Munich, we offer a wide range of both heated and unheated sapphires for you to choose from, fulfilling your heart's desire. Whether you're a jeweler or a gemstone enthusiast, we have the perfect options to cater to your needs!

Browse our Sapphire Collection or Send us an Inquiry for a customized Stone requirement.


Is heated or unheated sapphire better?

Heated sapphires offer a wider variety of colors and clarities compared to untreated sapphires. However, the better choice ultimately depends on personal preference, considering factors such as price and specific requirements.

Should a sapphire be heated?

A sapphire going through a heating treatment is quite common and widely accepted. However, if you desire to own a rarer gem, unheated sapphires are the way to go.

Are unheated sapphires worth more?

Yes, unheated sapphires are worth more compared to heated sapphires. This is because they are rarer and more difficult to find, which places them on the pricier end.

Are heated sapphires worth less?

Unheated sapphires are significantly rarer than heated sapphires, and therefore, command a higher price point. However, this doesn't necessarily mean that heated sapphires are worth less. It simply reflects that heated sapphires are the industry standard, with around 98% of the stones available in the market having undergone heat treatment.

How much are heated sapphires worth?

The value of heated sapphires varies depending on market factors. It's important to note that most sapphires available on the market have undergone heating. Therefore, heated sapphires are generally more affordable than unheated ones. Unheated sapphires, although pricier, are considered more valuable by collectors and gem enthusiasts due to their authenticity and rarity.

Do heated sapphires fade?

Heated sapphires, in general, do not fade under normal conditions. However, if exposed to high temperatures or secondary treatments, it is possible for the sapphire to fade.

Can you tell if a sapphire has been heated?

Yes, experienced gemologists can indeed determine whether a sapphire has been heated or not. Heated sapphires may show certain features that distinguish them from unheated ones, such as the absence of natural incisions that are typically present in unheated sapphires. An expert gemologist, with specialized knowledge and equipment, can observe these distinct characteristics and make an accurate assessment


Dr. Peter Janowski

Dr. Peter Janowski, Co-Founder of CEYLONS MUNICH, is a visionary in the gemstone industry. With a commitment to transparency, CEYLONS offers an exquisite collection of fine and fair sapphires, accompanied by detailed origin information. Peter's & Leander’s pioneering efforts led to the establishment of ECOMINE, the world's first self-sustaining mine for Fair Sapphires.

CEYLONS | MUNICH stands for the finest Ceylon sapphires. A brand committed to responsible mining of Sri Lankan gemstones obtained in an ethical manner.

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