How to Distinguish Between Real and Fake Gemstones
Whether you’re a budding gemologist or simply someone who loves to buy jewelry, distinguishing between real and fake gemstones can be a valuable skill. Here’s a basic guide to help enthusiasts discern genuine gemstones from their synthetic or imitation counterparts
Visual Inspection
  • Luster and Brilliance: Natural gemstones often have a unique glow or luster which can be difficult to replicate in synthetic stones.
  • Inclusions: Natural stones often have inclusions, which are tiny imperfections or ‘birthmarks’. While some high-quality synthetics also have inclusions, many are too perfect, and that itself can be a giveaway.
  • Color: Check the consistency and depth of the color. Natural stones can have color variations, while fakes might have uniform color.
Magnification
To perform this test, hold the ruby close to your mouth and breathe on it gently. Observe how long it takes for the fog to disappear. A real ruby should clear up within one or two seconds, while a fake ruby may take longer to clear.
Touch Test
Real gemstones are generally cold to the touch and will take a moment to warm up, whereas plastic or glass will feel warmer or more ambient.
Hardness
Gemstones are rated on the Mohs scale of hardness. For example, a genuine diamond can scratch glass, while a fake one can not.
Specific Gravity
Every gemstone has a unique density or specific gravity. This requires special equipment but can help confirm a stone’s identity.
Refractometer
Some gemstones will glow under UV light due to their fluorescence, while others won’t. This can be an indicator of authenticity.
Ultraviolet Light

Some gemstones will glow under UV light due to their fluorescence, while others won’t. This can be an indicator of authenticity.

Heat Conductivity
Diamonds are great conductors of heat. There are testers that check for this, which can quickly differentiate between real diamonds and fakes.
Certification

When buying an expensive gemstone, it’s wise to ask for a certification from a reputable lab or organization. These certificates validate the quality, origin, and authenticity of the stone. 

Modern Tools
You can also use the Rock Identify App to help identify rocks, minerals, and gemstones.
Common Imitations

Cubic Zirconia (CZ): Often used as a diamond substitute.
Moissanite: Closer to diamonds in hardness and brilliance but can be differentiated using specialized equipment.
Glass and Plastic: Used as cheap imitations for various gemstones.
Lab-Created Gemstones: These are real gemstones but are grown in labs. They have the same physical and chemical properties as natural gemstones but are usually flawless and less expensive.
Note: The above tests and indicators are general pointers. Some synthetic stones can be very convincing, so always consult with an expert when making a significant purchase or if authenticity is crucial.