If you are a bit of a chemistry geek like me and like to know random things...you will love this. "Do diamonds burn?" I'm going to explore how high heat, oxygen, and extreme temperatures can ignite and destroy diamonds and learn the science behind diamond combustion...well...because I can!

How did it start?

I went down the rabbit hole (in Weston Super Mare)...and it started with 'purple gold'...

I was visiting a friend last weekend and got fully obsessed with purple gold. Deep into the night, over enough tea to sink a ship and enough ginger biscuits to turn well...ginger...we discussed how you can make different coloured golds combining other alloys and I mean different colours, like purple and blue and pink, so we starting researching the processes. It was fascinating. Also extremely expensive and not for the weak hearted!

Note: I did have a play a few years ago trying to give some silver a blue gradient, but I didn't do the process myself, I paid someone 'waaaay waaaaay waaaaay' too much money to try it out. I was trying to get a tie dye effect, like the silver jewellery piece had been dipped. The outcome was cool but not permanent and that's what I was looking for, permanence.

Turning a 99.9% solid gold bar to powder...

My take away from the video I am about to share, (other than the coolness of the purple colouring in the end of the experiment), was how a solid chunk of gold can be dissolved in a solution called Aqua Regia (we will discuss this later in the blog) and can turn it into a powder.

Although you put it through the process of disintergrating the solid form into a power within a liquid and heat it, the cool fact is when you weigh it again, after the boling and drying processes, it is exactly the same weight as before to the milligram! Zero loss! That blew me away. 

See that cool video here from Nile Red: https://www.youtube.com/watch?v=d6Pcp944sRI

So then it got me thinking.....what about diamonds?

Do they burn and what does it look like? Do they melt? Explode? What?

So I went down the rabbit hole...AGAIN... and this is what I found out:

Diamonds burn in an oxygen-rich environment at temperatures between 850-1,000°F (455–537°C). If exposed to even higher temperatures, such as a jeweler’s torch, they can ignite and gradually turn into carbon dioxide (CO₂), leaving behind no ash. Nothing.

They literally vanish into thin air!

At high heat, the bonds between the carbon atoms begin to break. The carbon atoms react with oxygen in the air, forming CO₂ gas. Instead of melting into a liquid (like many other substances including gold and silver), diamonds simply disappear as they oxidize.

If a diamond is exposed to around 1,100°F / 593°C), it can become scorched or even completely burned away. This is why some diamonds recovered from fires appear cloudy or have a white, ashy coating. However, in low-oxygen environments (like being embedded in metal), they may survive but can suffer severe damage.

So then I asked the question, 'if the earth is super hot below, how do they exist deep in the earth without becoming a gas?' 

It turns out that the Earth's mantle is hotter than the burning point of diamonds and the lack of free oxygen, prevents them from igniting naturally underground, allowing them to be mined and extracted.

Diamonds are incredibly hard and chemically stable, but they can be dissolved or degraded under certain extreme conditions. Here are some substances and methods that can break down or dissolve diamonds that I found:

1. Molten Metals (Iron, Nickel, Cobalt)

• Diamonds can dissolve when exposed to molten iron, nickel, or cobalt at high temperatures (above 2,000°F / 1,100°C).
• This happens because carbon from the diamond dissolves into the molten metal.
• This process is used in industrial diamond synthesis and metal alloying.

2. Oxygen at High Temperatures (Burning Diamonds)

• When heated in pure oxygen at 850-1,000°F (455-537°C), diamonds will combust and turn into carbon dioxide gas.
• This means that in an open flame, a diamond doesn't melt but simply disappears as it burns.

3. Strong Acids Alone Won’t Work

• Diamonds are highly resistant to most acids, including hydrochloric acid (HCl) and sulfuric acid (H₂SO₄).
• Even the aggressive aqua regia (a mix of nitric acid and hydrochloric acid, which dissolves gold and platinum) has no effect on diamonds.

4. Molten Sodium Nitrate or Potassium Nitrate

• If a diamond is exposed to molten sodium nitrate (NaNO₃) or potassium nitrate (KNO₃) at 1,100°F (600°C) or higher, it will oxidize and degrade into carbon dioxide.
• This method is used in some laboratory experiments to study carbon oxidation.

5. Liquid Metal at Extreme Pressures (Inside the Earth’s Mantle)

• In the Earth’s deep mantle, diamonds may slowly dissolve in certain high-pressure liquid metal alloys over millions of years.
• This is why not all carbon in the mantle forms diamonds—some dissolves into the surrounding molten rock and metal.

6. High-Temperature Plasma (Graphitization Process)

• In a vacuum at extreme heat (above 1,500°C / 2,730°F), diamonds will slowly turn into graphite, which is a more stable form of carbon.
• This transformation happens at the atomic level and is called graphitization.

IMAGE: Rūdolfs Klintsons

What About Melting Diamonds?

• Diamonds don’t melt under normal atmospheric conditions.
• However, under high pressure (100,000+ atmospheres) and extreme heat (4,000°C / 7,232°F), diamonds can transition into a liquid carbon state, similar to how water turns to steam.
• This only occurs in lab conditions or deep inside giant planets like Jupiter and Neptune.

Along the way of looking at all of this cool chemistry, I also found out a few more fun facts about diamonds and here are some taster topics I will be exploring over the coming weeks in other blog posts. 

Diamond Fun Facts:

Not the Rarest Gemstone – While diamonds are marketed as rare, many gemstones, like alexandrite, red beryl, and jadeite, are significantly rarer.

Some Diamonds Are Over a Billion Years Old – Most natural diamonds on Earth formed between 1 to 3 billion years ago, deep in the mantle under extreme pressure.

Diamonds Can Be Fluorescent – Around 30% of diamonds glow under ultraviolet (UV) light, often emitting a blue glow, though some can glow green, yellow, or even red.

They Were First Discovered in India – The first recorded diamonds were found in India around 4th century BC, in riverbeds rather than mines.

Black Diamonds Might Be from Space – Black diamonds (carbonado diamonds) have unique properties that suggest they may have originated from meteor impacts or even formed in space before landing on Earth.

NEXT WEEK: We look at different coloured diamonds, with a focus on black diamonds, the perfect mens gem for our upcoming new designs from Felix this year. Hope you had a great read!