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.