Rough Diamond Buying Guide: How to Choose a Raw Diamond Shape - Rough – The Raw Stone

You’re ready to purchase a rough diamond, and you’ve searched through our site, and you’ve come upon a category of shape that is really not a shape at all - a “rough crystal”, so perhaps you’re wondering what this means exactly. Hopefully this post will give you some clarity, and inspire you to look more closely at our rough diamond crystals.

Rough diamond crystal

A classic example of a rough diamond crystal.

So, what is a rough diamond crystal?

This is a category of rough diamond that has no particular describable shape. It is unique, one-of-a-kind and its shape was formed through the natural process of the diamond crystalline structure’s growth over thousands of years, deep in the earth, under extreme pressure. Because of the nature of a diamond’s crystalline structure, some rough diamonds develop into describable shapes like dodecahedrons, octahedrons, cubes, rounds or triangles. However, in the case of the rough diamond crystal, the raw nature of the crystalline structure caused the diamond to shape into something completely new.

How would you describe the shape of a rough crystal exactly?

Specifically, raw diamond crystals are often modified forms of the octahedron, dodecahedron and cube shapes. However, they display rounded sides, points on the edges, and ribs throughout the structure. These modifications may make the diamond appear to have a completely different shape from its underlying structure, or, it may simply look like a rounded octahedron, or a jagged-edged dodecahedron.

Rough octahedron crystal with ribbed edges

An octahedron with ribs and raised rounded edges. Thus considered a rough crystal!

Where do these rough diamond crystalline shapes come from?

Rough diamond crystals are common to alluvial placer and river bed deposits. The rounded edges occur as a result of weathering and movement from their origin to the place where they are found. Unlike other types of diamond formation, these rough diamonds move from their original deposit through water or mud or other rocky earth to a new location, where they are found. The movement is what causes the change in shape over time.

Alluvial mining

An example of alluvial mining, or mining from a riverbed.

So now, please come take a look at our collection of rough diamond crystals. Perhaps you will find a one-of-a-kind stone that is perfect for you!

Whether you are shopping for a rough diamond for setting as is in rough diamond jewelry or for cutting and polishing into a beautiful polished diamond, a rough diamond crystal is an excellent choice. As always, please feel free to be in touch with one of our rough diamond specialists, we would be happy to assist you. You can email us at or call us directly at 1-415-841-2747 . We look forward to working with you to match your exact rough diamond needs!



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