04-30. Dolomite #1.

A strange flower coming down from the Italian Alps? Not quite – the mineral dolomite is named after Frenchman and mineralogist Deodat de Dolomieu in the mid-1700s.

Dolomite is the mineral for week #18 of the 52-week tour of the geometry of Nature. It is usually found in clusters of small rhombohedral crystals – small parallelepiped where all edges are the same length – and has a somewhat “saddle”-like shape. Its color varies from white to tan to pink. It’s part of the trigonal system family.

Dolomite is not often encountered as a gem. It is generally known as an inclusion in emerald, garnet, quartz, and ruby. A fascinating article by Luo, Yang and Shen describes its possible association with nephrite and how it was used in ancient Chinese culture. A major source of magnesium, it is found today in pharmaceutical applications and agricultural products.

From a resource by Steinfink & Sans: refinement of the crystal structure of dolomite.




04-28. Garnet #6.

The garnet structure is so well balanced and symmetrical, its geometry does make for traditional stain glass window template!

From a resource by Ross, Keppler, Canil and O’Neill.



04-25. Garnet #3.

What more to say!

The structure of this garnet crystal is so awesome, I just highlighted a few spots here and there.

Now, the most surprising for me is that antic and medieval jewelry takes so much after the geometry of the crystal, I wonder how they did it, not having any of the sophisticated instruments we have today to study nano-size objects.

There are 365 atoms, 642 bonds, 107 polyhedra in this image – not counting the few gems I inserted on the original geometry.

From a resource by Griffen, Hatch, Phillips and Kulaksiz.