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Image credit, Alrosa

X-Ray diamond sorting ‘behind the scenes’

Technology meets tradition.

Have you heard of X-Ray diamond sorting? If not, be my guest and travel behind the scenes to an alluvial diamond-mining operation overseen by our friends at Alrosa. They have provided an amazing video example of this efficient method of separating the wheat from the chaff, as it were.

Traditional sorting and separating of diamond-bearing ore has been done by grease-belt and exhaustive human hand-labor. With that said, check out this amazing 2016 video (thank you for this, Alrosa).

Here’s how it works

1. Diamond bearing ore is transported from aggregation at the mine’s source for processing.

Image credit: Alrosa

2. The ore is crushed to smaller, manageable sizes (Alrosa calls the process ‘crashing’ instead of crushing and I am good with that).

Image credit, Alrosa

3. The crushed ore is separated into lighter and heavier material through a process called dense media separation, which effectively brings the most likely diamonds to the front of the line.

Image credit, Alrosa

4. Pieces of ore are dropped in front of X-Ray emitters and photomultipliers. Why? Because diamond reacts to X-Rays, which triggers a response in the photomultiplier, at which point a puff of air redirects any diamond-bearing ore into a collection bin.

Image credit, Alrosa

In this manner, the material containing diamonds becomes concentrated and separated from “tailings,” meaning non-diamond bearing ore, which will become returned to the mining sites during rehabilitation.

I find the entire process, from extraction to processing to separation, to be fascinating. But don’t take my word for it. Scroll up and watch the video.

It’s a nice example of modern technology applied to a traditional industry dealing in billions-years old material. Pop some popcorn (but don’t let those X-Rays knock any kernels away from you!) and enjoy.

Angi Butler

Angi's first career was in diamond, gemstone and fashion jewelry sales. Now a corporate executive, she shares her advice and opinions on these pages.

This Post Has 5 Comments

  1. Hitindra

    good video showing the extraction process.


    I couldn’t resist commenting. Exceptionally well written!

  3. Tomasz

    Damn, Ive been looking for information like this for a while now. Thanks!

  4. Ingrid Harris

    The X-ray process for sorting diamonds was invented in 1936 by my father, John Henry Harris. He had just arrived at the Geological Survey Department, Dodoma, Tanganyika (then under British administration) for his first job as Research Metallurgist. This was one of the first things he did in a very long career around the world, ending at the United Nations. He never patented the invention (imagine!) but simply wrote it up and filed it in the library of the institute. After the Independence of Tanzania in 1961 this famous scientific library was raided by private mining companies supposedly on aid schemes and the paper on X-ray sorting of diamonds was stolen by the Russians (hence the appearance of this knowledge on this website) and by De Beers in South Africa. It is curious to think that my father never profited from his invention at all but that it is still after nearly a century the standard process by which all diamonds are sorted!

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