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The Geology of Diamonds

Geology of diamonds

The geology of diamonds

If you ask Merriam-Webster, “What the definition of Geology is?” Your answer will be along the technical terms of a science that studies rocks, layers of soil, etc., and to learn about the history of the Earth and its life.

This section will provide you with the background information on how the Earth’s activities have produced diamonds we find today.  So, let’s start by asking the first question that will lead us to a better understanding of how diamonds are formed.

What is the rock cycle?

The rock cycle is a never-ending process that takes liquefied rock called magma from deep within the earth’s mantle, and sends it through various steps to change it into certain minerals we know of today.


What are the three classifications of rocks?

Igneous rock- Igneous rock is formed through the cooling and solidification of magma.  And when magma from within the Earth’s surface is forced up out the top of the crust a volcano is created, and the magma is then called lava.

Sedimentary rock- Sedimentary rock is the accumulation of sediments formed from rock weathering.  The unique process consists of layers building up, and then become hard overtime when heat and pressure is added to the mixture.

Metamorphic rock- Metamorphic rocks have been modified by heat, pressure, and chemical processes usually while buried deep below Earth's surface.  Exposure to these extreme conditions has altered the mineralogy, texture, and chemical composition of the rocks.

How are diamonds formed?

Diamonds are formed in the static atmosphere of the Harzburgitic Region of the Earth’s mantle.  During the process of the rock cycle, after the magma is created from the extreme heat and pressure of the Metamorphic rock stage, the magma proceeds to cool down and recrystallize, creating small crystals from the carbon.

How do diamonds get to the surface of the Earth?

When an eruption of a Kimberlite pipe occurs, diamonds are diapered on the Earth’s surface, but there are some activities that take place deep under the Earth’s crust before the eruption occurs.

Magma, under its constant heat and pressure breaks loose and blasts upward towards the surface.  Along the way, the diamond crystals that were being formed from carbon are broken away by the super-fast-moving magma and carried upward to be scattered across the Earth’s surface in its host rock called Lamproite Breccia-Tuff.

What is Lamproite Breccia-Tuff?

Lamproite Breccia-Tuff, is the host rock that contains diamond crystals.  This host rock is described as having a dark brownish color with scattered yellow, tan, or whitish spots.  Lamproite also has a generalization name of, Pyroclastic Lamproite, due to it being part of the eruption of a Kimberlite pipe.

What other mineral can be found along with diamonds?

Depending on the geological location you are mining, there might be other indicator minerals that will help you out more to tailor your search efforts to be more effective in your area.

But in general, the minerals Quartz, calcite, magnetite, spinel, garnet, and the Olivine rock groups will be in a higher concentrated quantity around most Kimberlite pipe search efforts.  When you attempt to locate diamonds from glacier displacement these minerals can also be found, but not as much.


Being able to learn some geological facts about one of the Earth’s most astonishing gemstone, the diamond, and the way they are formed is the foundation to cultivating an excitement of a good old fashion treasure hunt that the whole family can enjoy.

To find out if this is true for your diamond adventure, researching the United State Geological Survey Office for area surveys is the best way to know what types of minerals that already have been found.

A special thank you to all geologist around the globe for the hard work you do! is privileged to be able to share your knowledge of our Earth for all to enjoy.




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2 thoughts on “The Geology of Diamonds

  1. Hey Y’all! Don’t forget to check out the eBook
    “How to Find Diamonds”

    Written by Kyle Sisson & edited by Nikita Senn. Great job guys!!

  2. Thanks Prospector! Lol.. It’s been a fun project, with a special thank you going to Nikita for all her help with the ebook!

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