How To Tell If A Gemstone Is Real

How To Tell If A Gemstone Is Real

At Martin Busch Jewelers, we understand the importance of authenticity when it comes to precious gemstones. Knowing how to identify a real gemstone can save you from making costly mistakes and ensure that you’re investing in a piece of genuine beauty and value. This guide will delve deep into various methods to determine if a gemstone is real, offering you the expertise needed to make informed decisions.

Understanding Gemstone Authenticity

Natural vs. Lab-Grown Gemstones

Natural gemstones are minerals that have formed naturally over millions of years. These gems are mined from the earth and are prized for their rarity and natural beauty. Lab-grown gemstones, while having the same physical, chemical, and optical properties as natural gemstones, are created in laboratories. They are generally less valuable due to their origin.

Commonly Tested Gemstones

The gemstones most frequently tested for authenticity include diamonds, rubies, sapphires, emeralds, and opals. Each of these stones has distinct characteristics that can help determine their authenticity.

Visual Inspection Techniques

Color and Transparency

The color and clarity of a gemstone can provide significant clues about its authenticity.

  • Consistent Color: Real gemstones often exhibit consistent color throughout. Variations or zoning can indicate that a gemstone has been treated or is synthetic.
  • Inclusions: Natural gemstones typically have inclusions, or internal flaws, which are indicators of authenticity. Synthetic stones often lack these inclusions or have very uniform inclusions.
  • Transparency: Genuine gemstones tend to have high transparency, though some may have natural inclusions that slightly impact clarity.

Surface and Cut

Examining the surface and cut of a gemstone can also reveal important details.

  • Luster: The luster, or the way a gemstone reflects light, varies between natural and synthetic stones. For example, diamonds exhibit an adamantine luster, whereas synthetic counterparts may not.
  • Facet Edges: The edges of a real gemstone’s facets are usually sharp and well-defined. Blurry or rounded edges can indicate a synthetic stone.
  • Polish Marks: Natural stones may show slight polishing marks, whereas synthetic stones often appear flawless.

Tools and Equipment

Jeweler’s Loupe

A jeweler’s loupe or magnifying glass allows for a closer inspection of a gemstone’s details.

  • Inclusions and Blemishes: Look for natural inclusions and surface blemishes. Synthetic stones typically appear too perfect.
  • Doubling Effect: Some gemstones, like zircon, exhibit a doubling effect where you can see doubled back facets through the stone. This is less common in synthetic stones.


A refractometer measures the refractive index of a gemstone, a key characteristic in identifying different types of stones.

  • Reading the Refractive Index: Each gemstone has a specific refractive index range. By comparing the measured refractive index with known values, you can identify the gemstone type.
  • Detecting Treatments: Refractometers can also help detect if a gemstone has been treated to enhance its appearance.

UV Light

Ultraviolet (UV) light can reveal certain properties of gemstones.

  • Fluorescence: Some gemstones fluoresce under UV light. For example, many diamonds will emit a blue glow, while some synthetic stones will fluoresce differently.
  • Color Changes: UV light can reveal color changes in certain treated or synthetic stones that are not visible under normal lighting.

Advanced Testing Methods


A spectroscope can analyze the light spectrum emitted by a gemstone.

  1. Spectral Lines: Different gemstones emit unique spectral lines. Comparing these lines with known spectra can help identify the gemstone.
  2. Color Origin: The spectroscope can also determine if the color of a gemstone is natural or if it has been artificially enhanced.

Thermal Conductivity

Diamonds, for instance, have high thermal conductivity, which can be measured with a thermal conductivity tester.

  • Heat Testing: This method is particularly useful for distinguishing diamonds from their imitations. Diamonds will disperse heat quickly, while imitations will not.

Professional Verification

Gemological Laboratories

For definitive verification, consider sending your gemstone to a gemological laboratory.

  • Certification: Reputable laboratories, such as the Gemological Institute of America (GIA) or the American Gem Society (AGS), provide certification that verifies the authenticity and quality of gemstones.
  • Comprehensive Analysis: These labs use advanced equipment and techniques to analyze the gemstone’s properties, ensuring accurate identification.

Consulting a Professional Jeweler

Visiting a trusted jeweler, like Martin Busch Jewelers, can also help you determine if a gemstone is real.

  • Expertise: Experienced jewelers have the knowledge and tools to evaluate gemstones accurately.
  • Reputation: Working with a reputable jeweler ensures that you receive trustworthy advice and service.


Determining the authenticity of a gemstone involves a combination of visual inspection, using specialized tools, and seeking professional verification. By understanding the key characteristics of real gemstones and utilizing appropriate methods, you can confidently assess their authenticity. At Martin Busch Jewelers, we are dedicated to providing you with expert guidance and high-quality, genuine gemstones. Visit our store or explore our website to learn more about our offerings and services.