What’s a Natural Diamond and How Were They Formed?


A natural diamond is one that was formed by nature.  This originally took place some 90 miles under the earth’s surface where temperature and pressures are extraordinarily high.  This process of development occurred roughly about 1-3 billion years.

Had these diamond stayed buried that far down in the earth’s crust, there probably would be no need to write this guide, since diamonds wouldn’t be a thing.

However, it is believed that volcanic eruptions brought these natural diamond closer the earth’s surface and some even found there close enough to be discovered by chance.  The majority, however, were and are still buried deep underground and remain embedded in a kind of rock called kimberlite.



How are Natural Diamonds Mined?

Once an active diamond mine is found–not an easy or inexpensive undertaking.  Excavating these diamonds is a huge job.  First, an enormous carrot-shaped hole is dug to locate what is known as the kimberlite pipe.  This pit is dug so that  roads hug the perimeter.  These roads are necessary to accommodate the gigantic machinery needed to excavate the terrific quantities kimberlite rock in hopes of finding embedded rough diamonds.  Below is a picture one of the largest mines ever dug.

The excavated kimberlite transported by huge dump trucks to sites where this rock is pulverized into tinier pieces and inspected to see if the any rough diamonds are embedded in the haul.  A very good mine will discover 1-3 carats of diamond per metric ton of kimberlite.  However, most of these diamond are not gem-quality and are used for industrial purposes.

There are only a handful of natural diamond mining companies in the world.  This is understandable considering the scale, cost and risk in finding and mining natural diamonds.  The largest of these companies is the DTC (Diamond Trading Company) formerly known as DeBeers.  The DeBeers name might be familiar to you from their iconic TV and print advertisements with the famous tagline “A Diamond is Forever”

The DTC sells rough diamonds directly to a select group of diamond manufacturers known as “Sightholders.”  These Sightholders cut and polish the rough diamonds to produce the finished diamonds we are all familiar with.


Just How Rare Are Gem-Quality Natural Diamonds?

Active diamond mines for geological reasons are usually located in very remote places around the globe with either very frigid or scorching hot climates.  These locales make exploration both difficult and costly.  Discovering a active diamond mine is risky and there are millions to be lost.

Due to the expense, risk and a diminishing supply of natural diamonds (the last active diamond mine was discovered over 20 years ago).  There is a built in scarcity to natural gem-quality diamonds.   In fact, very few gem-quality diamonds of certain sizes are actually discovered per year.

It is estimated that the number of gem-quality natural diamonds of a carat or more found in a given year would fit into an exercise ball.


This is not the case with lab-grown diamonds, which can be produced in abundant quantities.  As technology improves and competition increases it is predicted that lab-grown diamonds will go down in value.  

Natural diamonds are more expensive than lab-grown, but maintain or increase in value.  On the other hand lab-grown diamonds are less expensive than natural diamonds, but have historically lost value.