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How to Tell If A Diamond Is Real?

How to Tell If A Diamond Is Real

Buying diamonds is like a dream for many. You want to buy it to show your better half that you are ready to invest both monetarily and emotionally. Moreover, diamonds do not come cheap, especially the natural ones.

Then there is a demand for expensive products that people will try to make counterfeit for their benefit. You sure want to avoid getting scammed while paying for the real value. But how to tell if a diamond is real?

Well, there are several methods that you can try to prove its authenticity. Today we will test various tests that can help you identify whether it is real or not.

All the Effective Tests for Diamond Authentication

Home Test

Fog Test

  • Take a deep breath and see whether the moisture quickly evaporates off the diamond. Genuine diamonds emit heat at a quick rate.
  • Crystals and synthetic diamonds like cubic zirconia seem foggy for a few seconds.

Ink Test

  • A tiny dot should be drawn on the surface of the diamond using a ballpoint pen or a permanent marker.
  • A genuine diamond will not be able to attach to the ink, thus it will slip right off of it nearly immediately.
  • When the ink is applied to a false stone, it will smudge and leave a visible trail, and it will only be removed with a lot of work and cleaning products.

Icy Glass Test

  • Place an actual ice cube next to the diamond, and as soon as possible, study the diamond.
  • When put against the frosty glass, diamonds made of cubic zirconia and imitation diamonds will very immediately get coated in condensation and moisture.
  • In contrast, a genuine diamond will still seem to be “sweating-free” because it has a stronger surface tension, which prevents condensation from building up.

Float Test

  • The loose stone should be placed in a saltwater solution that is thick and contains more than one cup of salt for every gallon of water.
  • Diamonds that are not genuine will sink instantly, but genuine diamonds should float for a short period of time on the surface before sinking.
  • Authentic diamonds have a greater specific gravity, which makes it possible for them to have this fleeting floating illusion.

Water Test:

  • Draw a glass of water and place half of the diamond inside of it to create visual effects.
  • Genuine diamonds have outstanding light dispersion capabilities, which cause them to produce rainbow sparkles and dazzling flashes.
  • Diamonds packed with glass are unlikely to produce a fire that is colored and sharp.

Newspaper test

  • To see through the diamond’s crown, lay it on a piece of newspaper that is three to five millimeters thick.
  • If the text is too fuzzy to read through a genuine diamond, it’s because the diamond has a high refractive index to do its job of bending and dispersing light.
  • A fake diamond with poor refractive characteristics is indicated if the newspaper text is easily readable. Materials with less optical distortion include glass and quartz.

Professional Authentication

Jeweler Inspection

  • Following the guidelines established by the Gemological Institute of America (GIA), a professional jeweler will examine the diamond with a 10x jeweler’s loupe to evaluate its cut, clarity, color, and carat weight.
  • They can recognize poorer cuts, bubbles, carbon spots, and other imperfections in imitation diamonds that would not be present in a genuine certified diamond.
  • Visually distinguishing genuine diamonds from synthetic diamonds may also be accomplished by color gradation and tracing facets, culet, girdle, and crown alignments.

Spectrometer Analysis

  • The diamond is subjected to powerful ultraviolet light beams by a spectrometer, which records the resulting energy and spectral pattern on a graph.
  • Real diamond calibration graphs are used to compare the spectral return signature. Fake diamonds have flaws that deviate from the standard diamond specifications.
  • Accurate spectrometer certification involves specialized training and state-of-the-art equipment.

Thermal Conductivity

  • Take the diamond and press it between your hands or lay it on your heated skin for five to ten seconds.
  • Natural diamonds will have a notably chilly sensation when touched, as opposed to warming up when they come into contact with your hands.
  • Imposters such as moissanite are unable to release heat swiftly.

Precision Weighing

  • The carat weight of a genuine diamond must be proportional to the stone’s physical measurements to be considered authentic.
  • Those who work in the jewelry industry use sophisticated scales that have an accuracy of +/- 0.005 carats for measuring weight. Any irregularities might be an indication that diamond simulants include filler components that are used to modify the weight.

Ultrasound Testing

  • With the use of high-frequency sound waves, sophisticated ultrasound equipment are able to visually map and scan the interior structure of diamonds to identify any fake color injections, glass fillings, or other treatments that may have been applied.
  • Furthermore, during this ultrasonic mapping process, powerful microscopes can spot untreated natural growth defects that would be present in genuine diamonds but would not be present in artificial diamonds.

Electrical Conductivity

  • Testing at levels ranging from 5 to 20 S/m (Siemens per meter) reveals that natural diamonds are not very good at conducting electricity.
  • In terms of electrical conductivity, glass, and quartz are comparable to diamonds, with greater conductivities in the region of 500-100,000 S/m.
  • To establish the diamond’s legitimacy and assess its conductivity, a multi-tip electrical tester probes the diamond in different locations.

Fluorescence Testing

  • Fluorescence spectrometers are often used in the scientific community to test the response of a genuine diamond to ultraviolet light.
  • Under ultraviolet light, the majority of genuine diamonds display blue fluorescence, with intensities ranging from mild to medium to bright blue.
  • The presence of fluorescence or anything that is outside of the blue spectrum is indicative of a possible fake.

Hardness Testing

  • The superior density of real diamond, which is the material with the highest known grade of hardness, can be measured using electronic pressure scales.
  • On the Mohs scale, a genuine diamond is a perfect 10, meaning that it is capable of scratching any less dense substance.
  • When tested against actual diamond dust or tool tips, fake diamonds are shown to be inferior in terms of their scratch resistance and hardness.

Related: How to Tell If Pearls Are Real?

How to Evaluate Diamond’s Color Grading?

One of the four primary criteria (the “four Cs”) that are used to assess the quality and worth of a diamond is its color grading. The other three characteristics are the carat, the clarity, and the cut. Gemologists are responsible for doing color grading by visually comparing the stone to a master color grading set when the lighting and settings are under control.

The Gemological Institute of America (GIA), which grades diamonds on a scale that starts with D (colorless) and goes all the way down the alphabet scale to Z (light yellow/brown), uses this as its most popular color scale. Even though each grade step change is almost imperceptible, it has a very substantial influence on valuation:

  • D-F grades (colorless) – Highest value, premium prices
  • G-J grades (near colorless) – Most popular with white metals
  • K-M grades (faint yellow) – Affordable accent stones
  • N-R grades (very light yellow) – Noticeable color tinting
  • S-Z grades (light yellow/brown) – Visible coloration

An inexperienced eye should not be able to detect any color changes while the subject is facing up or down to an H-I grading point. The types of metals and the individual’s preferences determine the permitted color ranges when mounting diamonds. To determine the final color certification, a professional examination is still necessary.

Related: Platinum Vs Silver

How to Compare Online Database Registries for Diamond Authentication?

Checking online database registries adds an extra element of safety when examining the validity of diamonds before purchasing. There is a vast index of diamonds verified and graded by reputable worldwide organizations like GIA, AGS, and IGI, and the majority of high-quality diamond shops are subscribers to these registered services.

Database sites you can consult:

  • GIA Report Check.
  • You may get certifications and comprehensive quality evaluations with all four Cs metrics by entering GIA report numbers. The Gemological Institute of America has graded over four million loose diamonds.
  • Quality Document for AGS Diamonds.
  • Look for diamonds that have been certified by the labs of the American Gem Society in the quality documentation records. Jewelers use it to verify things.
  • Check for IGI Reports.
  • The IGI’s verification site screens over 15 million diamonds and grades more than 500,000 gemstones annually.

Before making a purchase, verify the item’s specifications, pictures, grading information, and certificate validity by comparing the report numbers given by vendors with these industry databases. Warning signs of diamond fraud include inconsistencies, unavailable entries, or vendors who refuse to provide certified grading report numbers. Verification of validity is facilitated by actively comparing registries.

Why look for GIA or IGI Certification on Diamond Authentication?

If you want to know for sure that the diamond you’re looking at is genuine, it’s a good idea to check for certification from reputable grading labs such as GIA and IGI. These third-party groups have the knowledge and special equipment to properly assess diamond quality in comparison to market norms.

GIA Certification

  • a non-profit organization that is widely regarded as the most authoritative source on diamond grading in the world
  • Examine and evaluate diamonds about the four Cs: weighing, cut, clarity, and color of the carat
  • Images, schematics, and identifying marks are all included in the security dossier package.
  • Within the GIA database, the report number may be verified.

IGI Certification

  • One of the major gem certifying associations, created in 1975.
  • Utilize the most recent technological advancements and international standards while conducting evaluations.
  • Under magnification, a laser engraving with the IGI emblem may be seen.
  • Culet, girdle, polish, and symmetry should all be manually inspected.
  • Analysis with a sophisticated spectrometer.
  • Look it up in the online report check system of the IGI.

What Markings to Look For Diamond Authentication?

When inspecting a diamond, several small marks may be used to identify its authenticity:

  • Laser Inscriptions: A logo, unique number, or identifying codes are often inscribed on girdles as a security safeguard by several respectable grading laboratories, such as GIA and IGI laser. Under 10x magnification, it becomes visible.
  • C) Etching: A visible ‘C’ etched by acid on girdles post-cutting indicates a naturally mined diamond. Protection against synthetics generated by humans that can be detected.
  • Holograms: As a measure against fraud, certification bodies may etch small holographic symbols into diamond girdles. Changing pictures may be revealed using state-of-the-art microscopes.
  • Structure: Expert gemologists examine diamonds under a microscope for telltale signs of artificial or natural origin, such as growth lines, additional facets, or other patterns.
  • Manufacturer ID: Under close inspection, certain synthetic diamonds—like those with the “Gemesis” carved into the girdle—bear the superscript emblems of well-known firms.


What tools to use for diamond authentication?

You may easily determine whether a diamond is genuine by using a 10x jeweler’s loupe, a blacklight, a heat probe, some saline solution, a flashlight, and several reference diamonds that are clean for comparison.

What technologies are used to detect fake diamonds?

Among the many high-tech detectors used by professionals are instruments for measuring electrical conductivity, thermal conductivity, spectrometers, ultrasonic mapping, and stations for overhead microscopy. These scientific tests determine the precise characteristics of genuine diamonds that synthetics cannot match.

Does the diamond glow under the backlight?

Not necessarily. Blue fluorescence, ranging from mild to medium-strong, is seen in around 20-30% of genuine diamonds when exposed to ultraviolet light. Possible forgeries are visible in the absence of fluorescence and any color beyond the blue range.


There is more than meets the eye when trying to identify a genuine diamond; there are a number of intangible characteristics that must be considered. Although at-home testing may be useful for preliminary inspections, consumers are safeguarded against sophisticated diamond fraud when they seek expert confirmation via authorized independent appraisers and advanced technology analysis. 

Acquiring essential assurance requires research into internet certification databases, careful examination of vendors, and familiarity with the microscopic marks, dimensions, and ideal proportions that are characteristic of genuine diamonds. It is best to stick with certified natural diamonds that have undergone evaluation by reputable international grading institutions when shopping for diamonds for the most peace of mind.