AS LOS ANGELES RESIDENTS try to salvage what remains of their ravaged homes after devastating wildfires swept through their communities this past week, you might be wondering about the condition of the diamond jewelry they may find in the ashes.
How a diamond ring survives a blazing inferno has a lot to do with the temperature of the fire and whether or not the jewelry was stored in a fire safe.
House fires typically reach 1,200 degrees Fahrenheit, but can get as high as 2,000 degrees in extreme conditions, such as the ones generated by the ferocious wind-whipped wildfires seen in California.
An average fire safe can protect its jewelry contents up to a temperature of 1,700 degrees Fahrenheit. And even without the safe, a gold and diamond ring may survive because the melting point of the precious metal is about 1,800 degrees Fahrenheit and the ignition temperature of a diamond is about 1,650 degrees Fahrenheit.
While diamond sits alone atop the Mohs scale as the hardest naturally occurring material known to man, it is made of carbon. And like other carbon materials, such as graphite or coal, diamond can burn.
Under regular conditions, the ignition occurs at about 1,650 degrees Fahrenheit. In a lab setting, when surrounded by pure oxygen, diamonds will start combusting at 1320 degrees Fahrenheit.
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In a 12-year-old YouTube video that has been viewed 719,000 times, British scientist and author Peter Wothers enlisted the help of Nobel prize-winning chemist Sir Harry Kroto to demonstrate what it takes to get a diamond to burn.
Wothers added a bit of drama and comic relief by using Kroto’s wife’s engagement diamond for the experiment. The viewer can see Kroto getting increasingly more uncomfortable as it becomes very clear that his wife’s diamond — under just the right conditions — has ignited.
In his preliminary experiment, Wothers easily set ablaze a bit of graphite using a torch in an environment of pure oxygen. Then he upped the ante by doing the exact same experiment using the Kroto engagement diamond.
Surprisingly, that lit up, too. The diamond burned as a golden ember without producing any flames. At that point, Kroto half-jokingly commented that he hoped Wothers could afford to pay for a replacement diamond.
As you might have figured out by now, Wothers had cleverly swapped the Krotos’ engagement diamond with a much lower quality specimen before the experiment began. (Kroto passed away in 2016 at the age of 76.)
On its website, the Gemological Institute of America (GIA) confirmed that house fires and jewelers’ torches can reach a temperature sufficient for a diamond to burn. It even provided an photo of what a scorched diamond looks like. Instead of being transparent, the diamond is marred by a white, cloudy surface (like frost on a window).
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The GIA noted that a diamond with this type of blemish can be recut, reducing the diamond’s size, but leaving no sign that it was ever damaged.
If you’re worried about how a diamond is protected when a ring setting needs to be retipped, for example, be assured that jewelers go to great lengths to make sure that the extreme heat of the torch does not affect the gemstone. Some jewelers use boric acid to protect the stone while others depend on the pinpoint accuracy of a laser welder to keep the diamond out of harm’s way.
