Diamonds, as you know, are extremely precious. Their high value partially stems from the fact that they’re already pretty rare – and only getting rarer.
Despite their elusive nature, diamonds can be found all over the world, but in just one type of rock. Is it lava rock? Can you find diamonds in lava rock?
Well, technically, no, but the full answer is a bit more complicated – and we had to write an entire article to accommodate it.
Whether you live in a volcanic region and want to look for diamonds, or you’re just a “mineral nut,” we advise you to scroll down and learn all about this topic!
What Is Lava Rock?
Lava rock – also known as volcanic rock – is a type of rock formed from lava that erupted from a volcano. It is considered a part of the igneous rock family (rocks formed from magma), but what sets it apart is that lava rock is made from erupted magma – or lava.
It covers approximately 8% of the current Earth’s land surface and can vary in color and texture.
Some of the most common lava rocks include basalt, rhyolite, and pumice. The former two got their names from their chemical compositions, while the latter was derived from the Latin word “pumex,” meaning foam, as it resembles a sponge.
The Controversy Surrounding The Term “Lava Rock”
The concept of “lava rock” is an artificial one. You see, in nature, such rocks are divided into metamorphic and hypabyssal rocks and are also a significant part of the sedimentary rock group.
Due to this, geologists sometimes view volcanic and some hypabyssal rocks as being one and the same.
Certain branches of geology use the word volcanic to describe only metavolcanic rocks, which is something entirely different from the term “lava rock” as we use it today.
Learn More: Can Lava Destroy A Diamond?
What Rocks Contain Diamonds?
Diamonds can be found only in two kinds of rocks – kimberlite and lamproite. Both of these are ingenious rocks – meaning, formed from magma – and originate from deep below the Earth’s surface. To be precise, they come from the upper mantle of our planet’s crust.
Diamonds are formed in high-pressure environments, which can be found 150 kilometers underground. We can’t dig that deep, though, so how are people able to mine diamonds?
Well, there are diamonds in the upper layers of the Earth, too, namely, its crust.
How did they get there?
The igneous rock containing diamonds (kimberlite) was pushed up by a deep-seated volcanic eruption a long time ago. Such eruptions are also known as kimberlite eruptions, and the most recent one is estimated to have happened around 10.000 years ago.
The already formed diamonds get brought up from the Earth’s mantle to the crust, traveling by magma, which is where we find them today. This process only occurs where the so-called “pipes” exist. These are rare types of volcanic vents through which the kimberlite magma flows from the depths.
On its way up, lava picks up tons of minerals and elements, much like floodwater collects silt. Diamonds are just one of the many things found in kimberlite rocks. The magma fills up the pipes and cools there, creating a long rock formation in the process.
The first of these pipes were found in Kimberley, South Africa. In case you were wondering, that’s where the rock formation got its name from.
Since this groundbreaking discovery, pipes have been found on nearly every continent. The biggest kimberlite mines are located in Australia, Africa – Botswana, Angola, South Africa – Russia, and Canada.
How Do People Find Diamond Sources?
Geologists rely on two methods for locating kimberlite pipes:
- The first – and the most reliable one – is mineral sampling. As mentioned, kimberlites contain many other things besides diamonds. These include various minerals like clinopyroxene, olivine, garnet, and many others. The geologists measure concentrations of some of the mentioned minerals in a specific location to determine whether diamond exploitation is possible there.
- The second – and more recent – method is called air magnetics. It is done from the sky, using special equipment installed on airplanes. The devices look for magnetic fields, which some elements found in kimberlites – such as magnetite – are known to produce.
This method allows for a quicker search across a larger swath of land. When combined with mineral sampling, it produces excellent results.
Related Read: What Are Negative Effects Of Diamond Mining?
Can You Find Diamonds In Lava Rock?
Now that you’ve acquired basic knowledge about rocks and diamonds, we can answer the main question.
Diamonds are normally not found in lava rocks. However, there is one recorded exception to this rule – and we will discuss it in a bit.
As we already mentioned, diamonds are found in kimberlite and some lamproite. Even though lava rocks and diamond-containing rocks are all igneous, their properties and formation methods are vastly different.
Lava rocks get fully formed above the Earth’s surface from the lava that a volcano has spewed out. On the other hand, kimberlite is formed below the surface, and most of it never sees the light of day – until they’re dug up, that is.
Volcanoes That Spit Up Diamonds
Even though lava rocks usually don’t contain diamonds, there was one instance when diamonds were found in such rocks. A very recent volcanic eruption spat out some diamonds, and scientists were puzzled.
It happened in Kamchatka, a far eastern province of Russia. This region is what geologists call a subduction zone – a place where the Pacific plate slides under the Eurasian continent.
That makes it a “fertile ground” for active volcanoes, stretching from Japan to Kamchatka. Two of the highly active Russian volcanoes are Klyuchevskoy and Shiveluch.
When a scientist called Erik Galimov and his team studied the aftermath of an eruption at Tolbachik, Kamchatka, which excreted mind-boggling amounts of lava, they were in for a surprise. They found tiny diamonds, less than 0.03 inches in size, stuck to the rocks made during the eruption.
Remember, this wasn’t a kimberlite eruption, and there was no kimberlite attached diamonds to be found. That means that the diamonds did not come from very deep within the Earth’s mantle, where they’re typically formed.
Where else could they have come from? That’s the big question, and Galimov has a few ideas.
By looking at the impurities in diamonds, the scientists realized that the elements they found matched those found in volcanic gases in that particular volcano. And that implies that these diamonds may have been formed from the very gasses released in the eruption.
The team checked if the diamonds were artificial and if they were residue from drilling instruments. However, the answer was negative; they were not synthetic. The theory that the diamonds were formed from gases was confirmed.
Crystallization from gases is by no means a new discovery, but this was the first time we saw diamonds made this way – and that’s how they ended up in lava rock.
All The (Known) Methods Of Diamond Formation
So far, humans have discovered four natural ways that diamonds form, and we would like to discuss them in this section.
Diamonds From The Mantle
We mentioned that kimberlite eruptions bring diamonds from the mantle up to the crust, but how are diamonds formed down there?
Diamonds are created in high-temperature, high-pressure environments. Such conditions can be found in parts of the Earth’s mantle, some 150 kilometers below the surface. The temperatures here reach around 1050 degrees Celsius.
Now, what’s important to know is that these ideal diamond-forming environments, commonly known as “diamond stability zones,” are not spread worldwide. They’re believed to be only under the interior of very stable continental plates.
So, the diamonds get formed, and they just sit there until a kimberlite eruption drags them upwards – but you already know how that works.
This method of diamond formation is the only one suitable for mass exploitation. The reason for this is that the crystals formed this way are large.
Those created in other ways are too tiny to be used either as gems or for industrial purposes.
Diamonds From Subduction Zones
Small diamonds have been found in rocks that might have been subducted by tectonic movements. The rocks are believed to have been pressed down then returned up to the surface where they were found.
Scientists say that diamonds formed this way are created at temperatures as low as 200 degrees Celsius and at only 80 kilometers deep. Some even suggest that seawater was a significant part of the process.
A study of blue diamonds which contain boron indicates that they might have been created by the subduction of oceanic crust.
Diamonds From Asteroid Impacts
As you may know, the Earth suffered quite a few asteroid hits throughout its long history. Each strike produced extreme pressures and temperatures.
For comparison’s sake, when an asteroid that’s 10 kilometers wide hits the Earth, it produces energy equivalent to a dozen nuclear blasts. And the temperature that it generates is greater than that of the Sun’s surface.
Such conditions are sufficient for diamond formation. This theory was confirmed when very small diamonds were discovered close to asteroid impact sites.
Diamonds From Space
Researchers from NASA discovered nanodiamonds in meteorites. A significant portion (around 3%) of all carbon in the meteorites was in nanodiamond form.
Of course, these diamonds are too tiny for use to be used in any way by humans.
On top of this, Smithsonian researchers, as they were cutting a sample from a meteorite, found tiny diamonds. They believe that they were formed in space collisions – not much different from those made at asteroid impact locations on Earth.
Can Diamonds Be Found On The Earth’s Surface?
We all know that miners have to dig to a significant depth to uncover diamonds.
But is it possible to find some on the very surface of the Earth? Something that you could do yourself?
The answer is yes! This method is called surface searching, and in the right location, you could stumble upon some staggering pieces.
The Crater of Diamonds State Park in Arkansas is one of the best places in the world to do this. The reason why it’s so good is that the caretakers plow the area every now and then, making it easier for searchers to find a precious stone.
The best time to look for diamonds in this park is after a rainstorm. The ground will be plowed before the rain, and as the water washes away dirt and light stones, the diamond will remain in place.
What are your chances of finding a good specimen, though? Pretty decent, actually. Over the past four years, 237 diamonds were found by visitors.
If you find yourself near a volcano, should you go looking for diamonds? Can you find diamonds in lava rock?
Sorry to break it to you; you’ll probably be wasting your time. Even if you go to Kamchatka and happen to find some diamonds, they will be so small and rough that they won’t be worth much.
We don’t want to be buzzkills here and discourage your adventurous spirit. If you want to go diamond hunting, please do! Just do your research first and make sure that the place you’re going to has diamonds.
Otherwise, you’re in for a disappointment.
While lava rocks might not contain diamonds, they do have gemstones like zircons, rubies, and so on. If you ask us, these are not half bad!