Want to know how to identify gemstones? The key lies in examining their color, clarity, hardness, and natural inclusions. Real gemstones like diamonds, sapphires, emeralds, and rubies exhibit unique optical properties, while synthetic stones may lack these natural features. Learn expert techniques to distinguish real gemstones from imitations.
How to Identify Gemstones: A Step-by-Step Guide
Gemstones captivate with their stunning colors and brilliance, but distinguishing between real and fake can be challenging. The market is filled with natural, synthetic, and treated gemstones, making it essential to verify their authenticity. Whether you’re examining a diamond, sapphire, emerald, or ruby, factors like color, inclusions, hardness, and optical properties play a crucial role in identification. This guide provides in-depth knowledge to help you recognize genuine gemstones confidently.

What Are Gemstones?
Gemstones are naturally occurring minerals or organic materials that display a range of colors and properties. Some of the most famous gemstones include diamonds, rubies, sapphires, emeralds, topaz, amethyst, and opal. These stones owe their beauty to different mineral compositions and trace elements. Understanding the properties of each gemstone is key to distinguishing them from synthetic or imitation stones.
Understanding Gemstones: What Are They?
Gemstones are precious or semi-precious minerals that are cut and polished for use in jewelry or decoration. They come in a variety of colors, shapes, and types. The most common categories include:
- Natural gemstones: Formed naturally within the Earth.
- Synthetic gemstones: Lab-created stones that mimic natural counterparts.
- Imitation stones: Materials designed to look like real gemstones but are made from different substances.
Proper gem identification ensures you can differentiate between these categories and understand the true value of the stone.
How to Identify a Real Gemstone
Checking the Color and Hue
Color is one of the first aspects to examine when identifying a gemstone. A natural sapphire exhibits a deep, vibrant blue, while emeralds have a lush green hue. If the gemstone appears too uniform or unnatural, it could be synthetic or treated.
Examining the Clarity and Transparency
Different gemstones have varying levels of clarity. Diamonds naturally contain inclusions, while emeralds often have visible fractures. If a gemstone appears flawless under magnification, it might be synthetic or glass.
Testing the Hardness of Gemstones
A gemstone’s hardness can be tested using the Mohs scale. Diamonds rank at 10, making them the hardest material, while opals range between 5.5-6.5. A simple scratch test against a known material can help differentiate softer stones from harder ones.
Looking for Natural Inclusions
Natural gemstones often contain inclusions that synthetic ones lack. Emerald inclusions are often described as “jardin” (garden), while rubies have needle-like rutile inclusions. A jeweler’s loupe or microscope can reveal these internal features.
Conducting a Light and Luster Test
A gemstone’s interaction with light can indicate authenticity. Diamonds have a high refractive index and exhibit strong brilliance, while opals display a play of color. The type of luster—whether glassy, silky, or dull—can help distinguish between different gemstones.
Essential Tools for Gemstone Identification
To properly identify gemstones, professionals use specialized tools. Here are the most important ones:
- Refractometer: Measures the stone’s refractive index.
- Polariscope: Determines whether the stone is singly or doubly refractive. Double refraction can indicate specific gem varieties.
- Loupe or Microscope: Magnifies the gemstone to inspect inclusions and surface features.
- Gemstone Identification Chart: A reference guide for comparing physical and optical properties.
- Specific Gravity Test: Measures the stone’s density and helps determine its type.
Pleochroism: Understanding Gemstone Color Changes
Pleochroism is a fascinating optical property found in certain gemstones like iolite and tourmaline. When viewed from different angles, these gemstones display varying colors, showcasing a captivating play of hues. This unique characteristic adds depth and intrigue to the gemstone, as it appears to change color depending on the observer’s perspective. Pleochroic gemstones often exhibit a mesmerizing range of colors, making them prized for their dynamic and ever-changing appearance.
Lab-Created vs. Natural Gemstones – Key Differences
Lab-created gemstones are made to mimic natural ones but lack the unique inclusions and chemical properties of real stones. Synthetic diamonds, for example, have metallic flux inclusions, while natural diamonds contain tiny carbon inclusions.
natural Gemstone Identification Techniques
Visual Examination
Examining a gemstone’s color, clarity, and general look in either artificial or natural light is called a visual examination. Gemologists enlarge gemstones for closer inspection using loupes and microscopes.
Gemological Testing
The physical and visual characteristics of a gemstone are examined via the use of specific tools and methods in gemological testing. These examinations might consist of:
A refractive index
A refractometer determines a gemstone’s refractive index, which offers important details on its provenance and identity.
What happens to light as it travels through a gemstone is measured by its refractive index. It is possible to identify gemstones by using their unique refractive indices.

Spectroscope
A spectroscope helps detect certain elements or impurities found in gemstones by analyzing the spectrum of light emitted or absorbed by the stone

Dichroscope
By dividing light into its two polarized components, a dichroscope analyzes a gemstone’s pleochroism and helps gemologists determine its distinct color characteristics.
How to Identify Different Types of Gemstones
How to Identify Real Jade
Real jade is either jadeite or nephrite, and both have a smooth, waxy texture. The easiest way to identify real jade is by its cool touch, high density, and toughness. Genuine jade gemstones should not scratch easily, as they are highly durable. When held against a light source, natural jade may show fine fibrous structures or subtle color variations, unlike fakes, which appear uniform. A sound test can also help—real jade produces a deep, resonant sound when tapped, whereas imitations sound dull.
How to Identify Gems
The best way to identify gems is by analyzing their physical and optical properties. Natural gems typically display slight imperfections, color variations, and unique inclusions. Gemstones like amethyst, peridot, and garnet show distinct hues and luster. If you’re unsure about a gem’s authenticity, a professional gemologist can conduct tests such as refractive index measurement, UV fluorescence, or specific gravity tests to verify if it is real.
How to Identify Raw Opal
Raw opal is often found in a matrix of rock and exhibits an uneven surface with veins of color running through it. A key sign of genuine raw opal is its play-of-color, a unique iridescence that shifts when viewed from different angles. Fake opals usually have a uniform, static color and lack the natural flashes seen in real opals. Additionally, raw opals are relatively soft and should not scratch glass easily.
How to Identify Rough Sapphire
Rough sapphire can be identified by its incredible hardness, second only to diamond. A real sapphire will not scratch easily and can cut glass. Most natural rough sapphires have a hexagonal crystal structure and appear in blue, yellow, or pink hues. They also have natural inclusions, while synthetic versions tend to be flawless. Holding a sapphire under bright light may reveal color zoning, which is common in natural stones but absent in lab-grown ones.
How to Identify Raw Emerald
A raw emerald has a distinct green color, often with slight bluish or yellowish tones. When identifying real emeralds, look for natural inclusions, known as “jardin,” which resemble tiny gardens or moss-like structures inside the stone. Unlike glass or synthetic emeralds, real ones do not have an overly uniform color. Emeralds are not as hard as diamonds or sapphires, so they should not scratch glass easily but will resist surface damage better than imitations.
How to Identify Raw Moonstone
Raw moonstone has a pearly, milky sheen known as adularescence, which creates a glowing effect when light moves across the surface. A genuine raw moonstone will exhibit this shimmer, while fake versions will appear dull. The stone is relatively soft, making it easy to scratch. Natural moonstones are often found in white, peach, or gray shades, with a slightly translucent quality.
Emerald: How to Identify Raw Jade
Jade and emerald are often confused, but raw jade is usually more opaque and waxy, whereas emerald is transparent with vibrant green hues. Unlike emerald, jade is much tougher and will not easily break under pressure. If you’re unsure, a scratch test can help—emeralds are harder than jade and can scratch materials that jade cannot.
How Do You Identify Gemstones
Gemstones can be identified by their color, hardness, specific gravity, and luster. Checking for inclusions under a magnifying glass can reveal if a gemstone is natural or synthetic. Professional tests like UV fluorescence and refractive index measurements help confirm authenticity. If you’re uncertain, consulting a gemologist is the best way to verify a stone’s identity.
How to Identify a Raw Ruby
A raw ruby is deep red with slight variations in tone and natural inclusions. It has a hexagonal crystal structure and is extremely hard, ranking at 9 on the Mohs scale. If you suspect a ruby is fake, try scratching glass—real rubies should not be easily scratched. Fake rubies are often made of glass or synthetic corundum and lack the brilliance of genuine stones.
How to Identify Jasper Stone
Jasper is an opaque variety of chalcedony that comes in various colors and patterns. Real jasper stones are dense, with unique banding, speckles, or swirls. Fake jasper often has an overly uniform color. If you wet a real jasper stone, the patterns remain visible and do not fade.
How to Identify Painite
Painite is an extremely rare gemstone that appears in reddish-brown or deep amber hues. Real painite has a high density and a vitreous luster. Due to its rarity, most painite specimens undergo lab testing to confirm their authenticity. If a stone is too cheap, it is likely fake.
How to Identify Raw Garnet
Raw garnet is typically deep red, orange, or brown and has a glassy luster. It is a hard stone and does not scratch easily. Natural garnets have visible inclusions and a high refractive index, giving them a bright sparkle when polished.
How to Identify Raw Sapphire
Raw sapphires are extremely durable and often appear with a rough, hexagonal shape. Their deep blue color may show zoning when viewed under a light source. Real sapphires should be able to scratch glass and resist acids.
How to Identify Real Crystals
Real crystals have natural imperfections, slight color variations, and unique internal structures. They feel cold to the touch and do not have a uniform, plastic-like appearance. Checking for bubbles inside a stone can help—natural crystals rarely have air bubbles, but glass imitations do.
How to Identify Real Opal
Genuine opal has a play-of-color that moves across the surface when tilted. Fake opals, such as synthetic ones, have a too-perfect pattern or lack this optical effect. Natural opal also has an irregular internal structure, whereas imitations look overly uniform.
How to Identify Real Turquoise
Turquoise has a distinct blue-green hue with a natural matrix of veins running through it. Fake turquoise is often dyed howlite, which lacks the authentic webbing and can fade over time. Real turquoise should not be overly glossy, as it has a matte, slightly porous texture.
How to Identify Sapphires in the Rough
Rough sapphires are highly durable and often exhibit a deep blue or yellow color. Real sapphires show color zoning and inclusions when examined under magnification. Their high hardness makes them difficult to scratch.
How to Identify Taaffeite
Taaffeite is an extremely rare gemstone that appears in pink, mauve, or lavender shades. It is often mistaken for spinel, but its double refraction helps distinguish it. Natural taaffeite is rarely found in jewelry, so if you encounter one, it should be lab-certified.
How to Tell Real Crystals
To determine if a crystal is real, check its temperature—natural crystals feel cold even in warm conditions. Authentic crystals have internal imperfections, whereas fake ones are too perfect. Another test is hardness—real quartz crystals, for example, can scratch glass, while fakes cannot.
FAQs – Quick Answers to Common Questions
Use a magnification test, hardness test, and UV light test to verify authenticity.
Diamond, ranking 10 on the Mohs scale.
Fake emeralds often appear too clear and lack natural inclusions.
Some sapphires fluoresce, but it depends on their composition.
Yes, many gemstones, including diamonds and sapphires, have synthetic versions.
No, but most natural gemstones have some inclusions.
A combination of color, hardness, and inclusion analysis is the best method.
They are usually less valuable than natural gemstones.
Diamond has the highest refractive index, making it the most brilliant.
Conclusion
Identifying gemstones requires careful analysis of their color, clarity, hardness, and inclusions. Understanding the key differences between diamonds, sapphires, emeralds, and other gemstones ensures you can confidently distinguish between natural and synthetic stones. Always consult a certified gemologist for professional verification.