Yes, many "fake" diamonds, like cubic zirconia (CZ) and moissanite, are hard enough to easily scratch a mirror, making the old "scratch test" unreliable for telling real diamonds from fakes, as modern simulants can pass it, potentially damaging the stone and mirror. While a genuine diamond (Mohs 10) will definitely scratch glass, so will many other durable materials, so this test isn't definitive, and it risks harming the stone, note this YouTube video and other sources.
Reality: Many materials, including fake diamonds, can scratch glass. This test can damage both the diamond and the surface it's tested on.
Diamonds are extremely hard, so if they easily scratch the glass, they are most likely real.
How to Identify a Real Diamond using a Mirror. This test, also known as a “scratch test” used to be considered the easiest way to test a diamond. The test is to simply scratch the loose stone against a mirror. The idea is that if the stone is hard enough to scratch the mirror, it's probably a diamond.
To determine a diamond's authenticity using a mirror, observe the mirror reflection test. Genuine diamonds display unique reflective quality, lack surface scratches, show no fogging effect, and their mirror symmetry highlights their real, unmatched brilliance.
The Aquamarine name comes from the Latin word for seawater and is said to calm waves and keep sailors safe at sea. It is sometimes referred to as a poor man's diamond because of the pale color.
The best fake diamonds are cubic zirconia (CZ), moissanite, and lab-grown diamonds. CZ is affordable and looks similar to real diamonds. Moissanite offers great brilliance and durability. Lab-grown diamonds have the same properties as natural diamonds but are more ethical and cost-effective.
However, some high-quality cubic zirconia can also scratch glass, so this test is actually not a definitive way to determine whether a diamond is real or not. Does cubic zirconia rust? Cubic zirconia does not rust and people often mistake a tarnished piece of jewelry as being rusty.
Taylor Swift's engagement ring features a large, antique Old Mine Brilliant Cut diamond, which is a vintage style with rounded corners, a high crown, and large facets, giving it a soft, candlelit sparkle rather than sharp modern flashes, often described as an elongated cushion shape with a small, open culet. This historical cut, popular in the 18th and 19th centuries, was chosen for its romantic, nostalgic character, perfectly suiting the ring's yellow gold setting with hand-engraved details.
When we shine a flashlight on a diamond, we're observing how the stone interacts with light. A real diamond refracts light in such a way that it sparkles with a gray and white brilliance, and can also cast rainbow colors onto a surface. The way a diamond reflects light is unique due to its high refractive index.
Diamonds are known for their hardness which is measured on the Mohs scale with a rating of 10. Diamonds are nearly scratch-proof and are one of the few gemstones that can endure damage from almost any other substance — with the exception of another diamond, of course.
So, genuine diamonds will scratch a mirror. On the other hand, so will quartz (7), moissanite (9.25), and cubic zirconia (8). Moissanite and cubic zirconia engagement rings are almost as hard as their diamond counterparts. Most well-made synthetic diamonds will seem authentic if you only use the scratch test.
Simulated diamonds are also known as diamond simulants and include things like cubic zirconia (CZ), moissanite, and YAG. They can also include some natural clear gemstones like white sapphire, white zircon or even clear quartz.
The "3-month ring rule" is an outdated marketing guideline suggesting spending the equivalent of three months' salary on an engagement ring, a concept created by De Beers to boost diamond sales, evolving from earlier one and two-month suggestions. Today, it's widely seen as a myth, with most couples prioritizing personal financial comfort, open communication, and meaningful choices over this arbitrary rule.
If you're willing to risk it, take a knife and gently scratch the surface of your stone. If it scratches immediately, the stone is synthetic. If there's no scratch, then you have a real diamond!
One common perception is that lab-grown diamonds are 'tacky' because they aren't sourced from the Earth. However, their formation process does not affect their quality or appearance. In fact, it's nearly impossible for even trained gemologists to distinguish between the two without specialized equipment.
No, a jeweler generally cannot tell if a diamond is lab-grown just by looking at it with the naked eye; they need specialized, lab-grade equipment like GIA iD100 or X-ray luminescence (XRL) testers to detect subtle differences in growth patterns, impurities, or fluorescence, as lab-grown diamonds share the same chemical and optical properties as natural diamonds. While some jewelers have machines to test, professional grading labs (like GIA) use advanced methods to identify them, often relying on laser inscriptions and grading reports for confirmation.
Red diamonds are the most expensive colored diamonds per carat, often exceeding $1 million per carat due to their extreme rarity. Only 20-30 natural red diamonds are known to exist worldwide.
Sapphires and rubies follow close behind diamonds with a rating of 9. From there, emeralds and aquamarines rate at a 7.5-8 in hardness, and another popular choice for non-diamond engagement rings, a pearl, rates at 2.5-4.5. As the number gets lower on the scale, the stone is referred to as being softer.
In terms of affordable diamond simulant, rock crystal quartz tops it all. Quartz or silica dioxide is one of the most abundant minerals on earth, and its uses range beyond in jewelleries. Its physical and chemical properties enable clear quartz to withstand physical and chemical weathering.
Pearl. Pearls have a hardness ratio that is between 2.5 and 4.5, making them the weakest of all gemstones.
If it scratches the glass, chances are good that the diamond is real. But, it's important to know that the scratch test could damage your diamond in the process. It's also not the most effective way to see if your diamonds is real since other gemstones can have the same effect on the glass.