The distribution of minerals and localities follows a distinctive pattern with a few very common minerals and many more rare species-a distribution that has led to the prediction that more than 1,500 mineral species occur on Earth but have yet to be discovered and described. The hunt is now on for these 'missing' minerals.
Here a network diagram for carbon-bearing minerals reveals previously hidden patterns in their diversity and distribution. Each colored circle represents a different carbon mineral. The size and color of the circles indicates how common or rare each mineral is on Earth.
Four examples illustrated are: (1) calcite, the commonest carbon-bearing mineral, which occurs at tens of thousands of localities; (2) malachite, a beautiful green ornamental copper carbonate mineral that is known from thousands of localities; (3) lanthanite, a carbonate of rare earth elements reported from only 14 localities around the world; and (4) the exceedingly rare calcium-zinc carbonate mineral skorpionite, which is known from only one locality in Namibia.
The black circles represent more than 300 different regional localities at which these minerals are found. The sizes of the circles indicate how many carbon-bearing minerals are found at each locality, and the lines link mineral species and their localities.