Apart from being one of the most gorgeous gemstones out there, diamonds are one of the best, if not the best thermal conductors. That means they absorb heat very well. So, the question is: Do diamonds melt ice?
It depends if the diamond is on its own or you hold it in your hand. If it’s alone, diamond won’t be able to melt the ice – but it’s a whole different story if you hold it in your hand and heat it up.
Let’s find out how thermal conductivity can help us determine whether the diamond is real or fake – and check out some other methods for testing your stone.
The Ice Melting Myth
Diamonds on their own couldn’t melt ice; it’s just their nature. However, their nature allows them to absorb the heat and transfer it quickly, in this case, to the ice that you would be touching with the diamond.
That would make the ice heat faster than usual, so, technically speaking, it may cause it to melt. However, the diamond could never melt the ice if the environment’s temperature is lower than the melting point.
So, it’s a “Maybe” – probably leaning more towards a “No.”
But that brings us to another fascinating property of these gems: The property of a diamond to absorb the heat is called thermal conductivity – and we’ve covered it in detail down below.
Related Read: Diamond Slang: Why Are Diamonds Sometimes Called Ice?
Diamond’s Thermal Conductivity
Diamond is an excellent conductor of heat because of strong covalent bonding and low phonon scattering. The thermal conductivity of diamonds was measured to be around 2200 W/m∙K.
That is ten times more than silver, by the way – and silver is already known to be the most thermally conductive metal. Yes, it even beats copper.
Due to the high thermal conductance, diamonds are used in semiconductor manufacture to prevent silicon and similar semiconducting materials from overheating.
At lower temperatures, the diamond’s thermal conductivity becomes even better. At a temperature of 104K, for example, a diamond’s thermal conductivity reaches 41000 W/m∙K.
The high thermal conductivity of these beautiful gemstones is used by gemologists and jewelers who may employ thermal probes to determine if the diamonds are genuine or not.
These probes consist of a pair of thermistors mounted on a copper tip. While one thermistor functions as a heating device, the other one measures the temperature of the copper tip.
If the stone that is being tested is a real diamond, it will conduct the copper tip’s thermal energy enough to produce a measurable temperature drop.
This process takes about two to three seconds.
However, older probes could be fooled by moissanite, a mineral from silicon carbide that was introduced as an alternative to diamonds – which, by the way, has similar thermal conductivity as diamonds.
Technologically, diamond’s high thermal conductivity is used for heat removal in high-end power devices. Diamonds are applied in situations where electrical conductivity can’t be tolerated – for example, the thermal management of high-power radio frequency micro coils.
Read Also: Will A Diamond Shatter If Heated?
How To Tell If A Diamond Is Real
Since we’re talking about thermal conductivity and how it can prove the “realness” of a diamond, we figured we should take a moment to discuss diamond testing.
While thermal conductivity is one way to test if a diamond is real or not, there are other methods to do so, too. Some can be done at home; others require expert assistance.
Let’s look at these methods.
Fog Test
For the fog test, hold your gemstone and breath on it with a puff of air. A light fog will form on its surface due to the moisture and heat in your breath.
If the fog disappears immediately, the stone is a genuine diamond. If it takes a few seconds for it to disperse, chances are, you have a fake.
As we already mentioned, diamonds effectively conduct heat, thus dispersing heat quickly.
Water Test
Simply find a standard drinking glass and fill it with water ¾ of the way. Carefully put your stone into the glass.
If the stone sinks, it’s a genuine diamond. However, if your stone floats underneath – or at the surface of the water – your stone is a fake.
Why? Well, a real diamond has a high density, which means it will always sink to the bottom. So, in that sense, the water test shows if your gemstone matches that high level of density or not.
Check The Setting
If a diamond is placed in a ring, check the type of setting and mount that’s used.
Due to a diamond’s large price tag, a real one would most likely be set in high-quality jewelry. For instance, a real diamond is usually set in precious metals, such as white gold, rose gold, and platinum.
To see if the setting is like what we described, search for markings inside the ring’s center. For example, the notes “10K,” “14K,” and “18K” specify the type of gold used. The notes “PT” and “Plat” indicate platinum.
If you see numbers such as 585, 770, 900, and 950, those are markings that specify platinum or gold, too.
However, if you see a “C.Z.” engraving, the gemstone isn’t a diamond but rather cubic zirconia.
See Also: Are Cubic Zirconia (CZ) Diamonds Fake?
Heating The Stone
Diamonds are a hard material – and will generally remain unresponsive when exposed to high heat.
To test this, fill the standard drinking glass with cold water. Use fire-proof gloves (or a set of plyers) to hold your stone. Heat the gem with a lighter for about 40 seconds, then drop it into the cold water.
If the stone shatters, it’s made of weaker components than diamond. Therefore, it’s not a real diamond. Fragile materials like cubic zirconium will crack or break due to quick expansion and contraction.
Think about the pyrex dish you use for cooking: If you pull it out of a hot oven and try to wash it right away, the shock temperature change will probably shatter the dish.
Diamonds are resistant to this high temperature, and the heat will disperse quickly, leaving the diamond unaffected by the change of temperature.
UV Light Test
To test your gemstone in a different way, place it under a blacklight and watch the reaction. Most diamonds will emit a blue glow when exposed to UV light – but not all of them.
Some diamonds don’t glow under blacklight. For this reason, if your stone doesn’t glow under UV light, it doesn’t necessarily mean it’s not a genuine diamond.
Since this test isn’t definite, it’s probably the best idea to have a jeweler or a diamond expert use their advanced equipment to test your stone.
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Test A Diamond Using Refractivity
When you see a diamond sparkle, you’re faced with its ability to refract light. When light hits the pavilions, it bounces and refracts up through the diamond’s table – and to our eyes.
When a diamond refracts light well and sparkles radiantly, that’s called diamond brilliance. Where are we going with this? Well, stones that are not diamonds won’t refract light very well. One example of such gemstone is cubic zirconia – which has less brilliance, if any, at all.
The following tests can show you the diamond’s refractivity – and, in turn, confirm its “realness.”
Newspaper Test
To test the stone’s refractivity, place it flat side down onto a page of a newspaper in a spot that has lots of lettering. Make sure the lighting is bright and that there aren’t any objects casting a shadow on the stone.
If you can read the letters of the newspaper, even if the letters are a bit blurry, the stone is fake. If the diamond is genuine, its facets won’t refract the light in a straight line but rather in different directions.
Because of this refraction, you won’t be able to read the letters in the newspaper through the diamond.
The newspaper test is commonly used on loose diamonds. If the diamonds are already set, consider using the following test we’re about to explain or have the gem inspected by a diamond expert.
The Dot Test
If you don’t have any newspaper to use, the dot test is an excellent alternative:
- Draw a small dot with a pen on a white piece of paper that’s placed on a flat surface.
- Lay your stone onto the dot with the flat side down.
- Look down onto the paper through the pointed end of the stone.
If you can see a circular reflection inside the stone, you might not have a real diamond.
Due to the diamonds’ powerful refractive qualities, light bounces in different directions instead of a straight line. That’s the reason why you can’t see letters or dots through a real diamond.
Test A Diamond Using Reflectivity
In addition to refractivity, you can test your stone based on its reflectivity.
While refractivity relates to the directions the light bounces, reflectivity refers to the quality and amount of light reflected off the gemstone. Reflectivity encircles both the brilliance and fire that shines off of a diamond’s table.
To test the diamond’s reflectivity, use the so-called sparkle test.
Sparkle Test
This test doesn’t require any equipment whatsoever – just your eyes. Hold your stone under a normal lamp and watch how light reflects off of it.
A real diamond will reflect white light extremely well, exhibiting exceptional sparkle. Diamonds also magnificently reflect colored light, by the way.
If you compare a real diamond to cubic zirconia, you’ll be able to notice a dramatic difference in the white and colored light sparkle.
Expert Methods
While various tests can be used to determine if a diamond is real or not, it’s advised to have a diamond expert assist you in concluding if you have a genuine diamond. An expert gemologist will be able to tell you for sure if your diamond is real or fake.
Bringing your gem to a diamond expert will give you peace of mind. There are several proven techniques and tools are used to work out if a diamond is genuine – including the ones outlined below.
Inspecting A Diamond With A Loupe
A diamond expert should always have access to a loupe – a special magnifying glass used for diamonds and other gemstones. When using it, a professional will look for imperfections and blemishes within the stone.
While a fake diamond can be perfectly made, a natural diamond will have minor imperfections called inclusions.
Testing A Diamond With High Profile Weighting
Gemologists and jewelers usually have a fine-tuned scale for measuring the most negligible differences in weight. The weight of fake stones like cubic zirconia will be higher than a real diamond.
To perform this test, select a fake stone that’s approximately equal in size and shape. Use this stone as a comparison for the stone you’re considering.
Test A Diamond With Electrical Conductivity
Detecting a fake diamond can be achieved through an electrical conductivity test performed by a professional. Diamonds do NOT conduct electricity, unlike some other gemstones – including synthetic moissanite.
A tester used for this will provide a clear sign as to whether the diamond is real or fake. A diamond won’t exhibit electrical conductivity while other gemstones, like cubic zirconia, will.
Read More:
Is A Scratch Test Reliable?
The scratch test was a widely used method that aimed to assess the hardness of a gemstone. The test involved scraping a gemstone along a mirror to see which one develops a scratch first.
Diamonds are rated “10” on the Mohs scale of mineral hardness. Still, fakes like cubic zirconia and moissanite don’t fall far behind them.
And for this reason, the scratch test isn’t very reliable. You’re better served to use tests like thermal conductivity tests – or have the stone inspected with a professional loupe.
Bottom Line
You came here today with a pretty strange question on your mind – “Do diamonds melt ice?” We hope that we’ve offered you a lot more knowledge than you might’ve expected to find.
And now, to recap:
It turns out that it depends if the diamonds are on their own or are being held by someone.
A diamond on its own can’t melt ice. But due to the diamond’s exceptional thermal conductivity, it’s going to melt ice when held in hand and warmed up. That’s because diamonds are super-efficient at absorbing the surrounding heat. Therefore when you hold a diamond next to the ice, the ice is going to melt faster.
Diamond’s thermal conductivity is used to test if the stone is real or not. Apart from it, there are various other tests that you can do at home to determine if you have a genuine diamond – or just a good-looking fake.
The best thing you can do if you have doubts about your stone’s realness would be to take it to a professional; they’ll be able to tell you for sure.