Published: January 4th, 2026

Detailed recommendations from AD Jewelry specialists on how to independently determine the authenticity of gemstones and precious metals without specialized equipment. Learn about visual signs, natural features, the behavior of stones and metals, and best practices for initial jewelry inspection at home.

Professional Advice from AD Jewelry Experts (Illinois)

Natural gemstones are the result of geological processes spanning many years. Therefore, every natural stone has certain characteristic features: microscopic inclusions, specific coloring, a particular play of light, and a unique structure. Such features are impossible to perfectly simulate artificially-and primary diagnostics rely precisely on these signs.

Most fakes visually mask their inauthenticity, but often reveal themselves in the details. Therefore, the first thing to do is to carefully inspect the stone. The experts at AD Jewelry in Illinois deal with both natural items and fakes daily and know well which signs can be spotted with the "naked eye."

Let's review the experts' recommendations that will help you make a preliminary assessment of the quality of stones and metals.

What You Need to Pay Attention To

1. Color

Natural Stone. It has a complex, heterogeneous color and may contain light areas of saturation. When rotated, the hue may slightly "play" with natural transitions-from lighter to darker.

The color of a gemstone is never absolutely uniform. Even the highest quality stones retain a natural range of shades.

Fake. A fake can be recognized by its overly uniform saturation, noticeable unnatural chemical sheen, and lack of areas of slight desaturation. 

For example

  • Glass-based ruby imitations are usually too "red."
  • Fake sapphires look "painted."
  • Cubic zirconia easily gives itself away with its play of light and excessively high brightness.

2. Transparency and Inclusions

Inclusions are the main natural sign.

Natural stones are almost never perfectly clean. They feature inclusions in the form of feathers, clouds, pinpoint speckles, or small growth "channels" and gas-liquid inclusions. These microscopic signs indicate the natural origin of the stones.

Synthetics and Fakes. A fake made of glass contains air bubbles (round, with smooth borders). Cubic zirconia is almost always perfectly clean, and synthetic stones do have inclusions, but they are repetitive and look "too perfect."

If you notice air bubbles upon inspection, it is a 100% glass imitation and not a natural stone.

3. Play of Light and Luster (Brilliance)

Every gemstone has its own special character in how it manifests light.

For example:

  • A diamond is distinguished by a "hard," bright, and intense luster.
  • Cubic zirconia is characterized by a more "rainbow-like," often excessively iridescent sparkle.
  • Sapphire has a vitreous, moderate luster.
  • Ruby's luster is warm and saturated.
  • Due to numerous inclusions, the luster of an emerald is soft and slightly matte.

If a stone reflects light too brightly or unusually for that mineral, it is a cause for suspicion.

How to Recognize a Noble Metal

Jewelers often identify metals without measuring instruments, simply by looking at the metal's color, density, surface features, degree of oxidation, luster character, and hallmark. These signs are accessible to everyone.

1. Gold Inspection

Real Gold has a deep, warm hue. It does not tarnish or oxidize, does not change color with prolonged wear, and does not leave marks on the skin. Gold is soft, so microscopic signs of use-slight scratches, small scuffs-are visible on the jewelry over time.

Fakes-copper-plated alloys-quickly rub off, and dark spots appear. Their shade is duller or too yellow. They may leave a green mark on the skin when worn.

If the item looks "too new" after prolonged wear, there is a high probability that it is a gold-plated fake.

2. How to Distinguish Real Silver from Imitations

Real Silver has a soft metallic luster. It may tarnish (oxidize) over time but is easily cleaned. It is characterized by a distinct cold hue, with a slight clouding noted upon contact with air.

A Fake is characterized by the coating peeling off and an overly mirror-like sheen. Such items may exhibit a yellowish tint and uneven oxidation. If a fake has been covered with a thin layer of silver, checking this is elementary: in areas of active contact, the metal beneath the coating will be a different color.

3. Platinum

Platinum is the most easily recognizable metal for a jeweler. Its authenticity can be determined by characteristic signs: very high density (it weighs noticeably heavier than gold), and it is distinguished by a matte, steel-like luster. It does not change color at all and is hardly scratched by small objects.

Fakes usually "give themselves away" by weight: they are noticeably lighter.

At-Home Tests Without Equipment

These practical actions at home are safe for the jewelry and accessible to everyone.

1. Hardness Test

Tests should only be conducted on very inconspicuous areas or with no contact at all.

  • Diamond is harder than all natural stones. If you see deep scratches on the surface, it is definitely not a diamond.
  • Sapphire and Ruby are very hard; they are not scratched by glass.
  • Glass and Cubic Zirconia easily acquire microscopic damage.

Using sharp objects is not recommended - it can damage the item.

2. "Non-Instrumental Thermal Conductivity" Test

This is a basic test that genuinely works without professional equipment.

  • A Diamond almost instantly adopts the temperature of your fingers. At the same time, the cold sensation instantly "disappears."
  • Glass and Fakes remain cold significantly longer. They heat up slowly.

This is one of the simplest tests for home conditions.

3. Fogging Test

This is very effective for diamonds.

  • A Real Diamond does not fog up or fogs up for a fraction of a second. It instantly "dispels" moisture.
  • Cubic Zirconia, Glass, Imitations fog up like ordinary glass.

4. Reflection Check on a White Sheet of Paper

This test helps distinguish a diamond from cubic zirconia.

  • A Diamond gives off-white sparks - bright but cold flashes.
  • Cubic Zirconia gives off multicolored, rainbow-like flashes, sometimes "too beautiful."

If the sparkle looks excessively "spectacular," it is not a diamond.

Common Fakes and How to Spot Them Visually

An experienced jeweler can easily distinguish a fake even before tests after numerous diagnoses. There are several signs by which you, too, can identify an imitation.

1. Glass Imitations of Stones

Characteristic signs

  • Bubbles.
  • Liquid facet edges.
  • Poor clarity of reflections.
  • Very low hardness.
  • Dull luster.

Emeralds, rubies, and sapphires are most often made from glass.

2. Cubic Zirconia: The Diamond's Main Competitor in Fakes

Cubic zirconia is very beautiful, but it does not behave like a diamond. 

Distinguishing signs

  • Rainbow brilliance of flashes.
  • Excessively strong play of light.
  • Absence of microscopic inclusions.
  • Too ideal clarity.
  • Poor heat retention.

Natural diamonds do not have such a "Hollywood" sparkle.

3. Moissanite: The Complex "Double" of a Diamond

Moissanite is the best diamond imitator. It is difficult to distinguish without instruments, but possible. 

Distinguishing signs

  • Upon careful examination, you may notice a "double reflection."
  • The play of light is richer than a diamond's.
  • The luster is slightly warmer.

A diamond is characterized by a more strict and cold luster.

Why It Is Important to Turn to Professionals

Checking the authenticity of jewelry without instruments is a difficult but achievable task. By using the advice of AD Jewelry specialists, you will be able to:

  • Distinguish natural stones from imitations.
  • Determine the plausibility of a stone's origin.
  • Identify metal fakes.
  • Detect glass and synthetic analogs.
  • Preliminarily assess the condition of the item.

But it is always important to consult professionals to confirm authenticity. For accurate diagnostics, experts use professional modern equipment.

  • Spectrometers.
  • Refractometers.
  • High-precision microscopes.
  • Metal analyzers.
  • Ultrasonic inspection.

If you need to assess a stone's authenticity, identify a metal, get a professional appraisal, and receive an official document, the AD Jewelry branch in Illinois can help perform a complete analysis of the jewelry and provide an accurate conclusion.

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845 West Dundee Rd, Wheeling, IL 60090