October 31, 2023
How To Identify Rough Sapphire (Image by International Gem Society)

How To Identify Rough Sapphire

How to identify rough sapphires
Source: Pinterest.com

Have you ever gazed at a sapphire and wondered if it's the real deal or just an imitation? As the demand for sapphires continues to rise, the market is flooded with various imitations, making it essential to know how to identify rough sapphires. 

In this blog, we will delve into the art of identifying authentic rough sapphires and equipping you with the knowledge and tools necessary to navigate the gemstone market. Whether you're a gemstone enthusiast or a prospective buyer, we have you covered!

What Is Rough Sapphire?

Rough sapphire refers to sapphires that are in their natural, uncut state, directly mined from the earth. Unlike cut and polished sapphires, which have undergone shaping and faceting processes to enhance their appearance, rough sapphires retain their original form. These unrefined gemstones showcase the raw beauty of sapphires, with their natural color, shape, and texture.

So if you’re thinking of purchasing a rough sapphire, here are a few points to consider:


• More affordable - Rough sapphires are generally cheaper compared to their cut and polished counterparts. However, please remember that the price range for rough sapphires can vary based on multiple factors, including quality and texture. This makes it challenging to specify a price range for rough sapphires.

• Design your own sapphire - You can be part of the creative process, as you can choose the design and style of the final cut gemstone. 


• Requires specialized skills and equipment - Rough sapphire requires specialized skills and equipment for cutting and polishing. This process is usually taken care of if you’re purchasing a cut and polished sapphire. 

• Time and cost-consuming - Since you have to do everything from scratch and get to be a part of the creative process, it involves additional time, effort, and costs in comparison to purchasing a cut and polished sapphire. 

• Uncertain Outcome - The process of cutting sapphires can be challenging as it requires years of experience, thus the outcome can sometimes be uncertain.

Characteristics Of Rough Sapphire

Rough sapphires possess distinct physical and visual characteristics that help in their identification. These characteristics encompass color, shape, texture, crystal structure, transparency, inclusions, carat weight, cleavage, fracture, and hardness. Let's explore these features in more detail,

Characteristics Of Rough Sapphire
Source: Pinterest.com

• Shape: Rough sapphires exhibit irregular shapes, reflecting their natural formations and crystalline structures. They often resemble uncut crystals or rocky fragments. Each rough sapphire's distinct shape contributes to its individuality and inherent natural allure.

• Texture: The texture of rough sapphires can vary, ranging from smooth to rough, contingent upon the conditions during their formation. Some rough sapphires may display natural surface inclusions or rugged edges. By running your fingers across the surface, you can perceive the texture and detect any irregularities or natural formations.

Sapphire Texture
Source: Pinterest.com

Color: Rough sapphires display a wide array of colors, encompassing blue, yellow, pink, green, and more. Within a single rough sapphire, the color may vary, exhibiting different hues or color zoning. For example, blue sapphires may present variations in shade, ranging from pale blue to deep royal blue. It is important to note that while color provides valuable clues, it alone does not serve as a definitive indicator of authenticity.

Sapphire Color
Source: Pinterest.com

• Crystal Structure: Rough sapphires possess a crystalline structure that follows a trigonal pattern. Their hexagonal or barrel shapes are indicative of their crystal structure, with surfaces that can be flat or uneven.

• Transparency: The transparency of rough sapphires spans a broad spectrum, ranging from opaque to transparent. Highly valued sapphires exhibit transparency and good clarity.

How To Identify Rough Sapphire
Source: Pinterest.com

• Inclusions: Inclusions or natural imperfections are commonly found within rough sapphires. These inclusions can encompass mineral crystals, minute fractures, or color zoning. The type, size, and location of these inclusions influence the value and appearance of the sapphire.

• Carat Weight: Rough sapphire crystals come in varying sizes, and larger crystals generally yield larger faceted gemstones. Carat weight plays a significant role in determining a sapphire's value.

How To Identify Rough Sapphire
Source: Pinterest.com

• Cleavage and Fracture: Rough sapphires possess distinct cleavage and tend to fracture along planes parallel to their crystal structure. Once cut or polished, sapphires exhibit a conchoidal fracture reminiscent of glass.

• Hardness: With a rating of 9 on the Mohs scale, sapphire is a durable gemstone, highly resistant to scratches, making it suitable for everyday wear.

By closely examining these distinctive characteristics, you can acquire valuable insights into the authenticity and genuineness of a rough sapphire.

Tools For Identifying Rough Sapphire

Did you know that there are specific tools that you can use to identify rough sapphire? Here are a few tools that can help make your life easier.

• Jeweler's Loupe: A jeweler's loupe is a small magnifying tool that allows for a close examination of the rough sapphire. It helps you observe the gemstone's internal features, such as inclusions and color zoning patterns.

• Microscope: A microscope provides a higher level of magnification and clarity compared to a loupe. It allows for a more detailed view of the rough sapphire, enabling precise observation of both internal and external features.

• Refractometer: A refractometer is a tool used to measure the refractive index of a gemstone. By assessing the refractive index of the rough sapphire with established values for genuine sapphires you can confirm its authenticity. A general range for the refractive index of sapphires is approximately 1.76 to 1.78.

• Specific Gravity Tester: This tool measures the density or specific gravity of a gemstone, which can provide further clues about its identity. By comparing the specific gravity of the rough sapphire to known values, gemologists can gain insights into its mineral composition and potentially differentiate it from other similar gemstones.

• Hardness Testing Tool: A hardness testing tool, such as the Mohs hardness scale, helps determine the relative hardness of a gemstone. By testing the resistance of the rough sapphire to scratching or being scratched by other minerals of known hardness, you can assess its hardness level.

• Ceramic Streak Plate: A ceramic streak plate is a hard, unglazed plate used to examine the streak color of a mineral. By rubbing the rough sapphire against the plate, it leaves a streak that can help identify the gemstone.

Fun fact, the best tools for determining rough sapphires are a combination of the refractometer and specific gravity tester. However, it's important to note that accurately identifying a rough sapphire requires years of experience. Therefore, we recommend seeking the help of an experienced gemologist.

How To Identify Rough Sapphire

Now that you have a good understanding of how rough sapphires look like. Let’s take a look at how to identify rough sapphire. Here are a few measures that you can take:

• Assess the crystal structure: Examine the rough sapphire for its crystal structure. Genuine rough sapphires have clear and distinct crystal shapes, like hexagonal prisms or flat shapes.

• Conduct a visual examination: Carefully observe the rough sapphire's visual appearance. Look for any distinct features like color zoning, which refers to variations in color within the stone. Genuine rough sapphires may display color zoning due to the uneven distribution of trace elements during their formation. You can use a microscope or loupe for this.

• Perform a hardness and scratch test: Use a hardness testing tool, such as a mineral hardness kit like the Mohs hardness scale, to determine the stone's hardness. Sapphire has a hardness of 9 on the Mohs scale, which means it can scratch materials with a lower hardness. Conduct a scratch test by attempting to scratch the rough sapphire with known materials of lower hardness. If the rough sapphire remains unscratched, it is likely genuine.

• Check for pleochroism: Hold the rough sapphire against a light source and rotate it to observe any pleochroic effects. Genuine sapphires often exhibit pleochroism, which means they display different colors when viewed from different angles.

• Conduct a streak test: Use a streak testing tool, such as a ceramic streak plate, to determine the color of the streak left behind when the rough sapphire is scratched on the plate. Genuine sapphires usually leave a white streak.

• Inspect the surface: Examine the surface of the rough sapphire for any natural imperfections, such as inclusions, fractures, or growth lines. Genuine rough sapphires often have these characteristics, which can be indicators of authenticity.

• Test specific gravity: Measure the specific gravity of the rough sapphire using a specific gravity testing device. Genuine sapphires have a specific gravity of around 3.98-4.06 g/cm³, while imitations may have different values.

• Seek professional gemological testing: If you want a definitive confirmation of the rough sapphire's authenticity, consider getting it tested by a professional gemologist. Gemological laboratories have advanced equipment and expertise to conduct detailed examinations, including spectroscopy and microscopic analysis.

It is important to note that identifying rough sapphires accurately may require expertise and experience. When in doubt, always consult with a professional gemologist.

Explore Ceylon Munich's Genuine Sapphire Collection

Now that you’re equipped with the knowledge and tools to identify genuine rough sapphires, by understanding the characteristics of rough sapphires, such as their color, shape, and texture, you can confidently assess their authenticity. Remember to use tools like a jeweler's loupe, microscope, and refractometer to examine the unique features of each stone.

Identifying rough sapphires not only ensures that you invest in genuine gemstones but also opens up a world of creative possibilities. With rough sapphires, you have the opportunity to be part of the journey, selecting the design and style of the final cut gemstone.

Once you’ve successfully identified and acquired your authentic rough sapphire, the next crucial step is to understand the art of sapphire cutting and polishing. Sapphire cutting and polishing requires is a meticulous craft that requires specific skill and precision, that can take your sapphire to the next level.

So, whether you're a passionate gemstone enthusiast looking to expand your collection or a discerning buyer in search of the perfect sapphire for your custom-designed jewelry, Ceylons Munich is your trusted destination. We are dedicated to providing you with ethically sourced sapphires of the highest quality, backed by our commitment to responsible mining practices and the well-being of local communities

Check out our Sapphire Collection or learn more about sapphires


What does sapphire look like in nature?

Sapphires are mostly blue in color but also come in a wide array of colors such as yellow, pink, and green. Within a single rough sapphire, the color may vary, exhibiting different hues or color zoning.

How hard is raw sapphire?

On the Mohs hardness scale, sapphire has a hardness of 9 on the Mohs scale.

What color is raw sapphire?

Raw sapphires are usually blue in color but they can also come in many other colors like yellow, pink, purple, violet, yellow, and green.

How do you clean raw sapphires?

To clean raw sapphires, start by using warm water and a gentle detergent or non-abrasive jewelry cleaner. Gently buff the surface of the gem with a soft cloth or brush. This is mainly because most sapphires are heat-treated and should be handled with care.

What does a crack in a sapphire look like?

When examining a sapphire, a crack can be identified by its unique light reflection properties. When a sapphire has a crack, it tends to display a spectrum similar to a rainbow upon exposure to light.


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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