How Minerals Work
How Minerals Work
We might expect the ground of vineyards to consist of bewildering permutations of elements, but because its composition is dominated by just eight of them and there are chemical restrictions on how they can combine, the number of common minerals is not huge. Even so, their names are not particularly well known, even those of the very minerals that make the ground we live on and the soils that vines grow in. Mineral names that might spring to mind are more likely to be those used in jewelry or that are commercially mined. Such gemstones and ore minerals are not widespread, but geological processes have concentrated them in certain parts of the Earth, and if we can locate these accumulations, it may be worthwhile to extract them for profit. The rocks and soils that mainly concern us here are composed of silicate minerals, and Chapter 3 is devoted to these workhorses. They are sometimes called the “rock-forming minerals,” though there is an outstanding exception to this term: calcium carbonate, which makes the calcareous rocks. So in this chapter’s survey of the kinds of nonsilicate minerals we may come across in vineyards, we will pay particular attention to the carbonates. But first, let’s examine some fundamental concepts concerning the nature of minerals. As we saw in Chapter 1, minerals are made of ions bonded together through giving or sharing electrons. But to achieve this linkage, the ions cannot combine in some higgledy-piggledy fashion; rather, they have to organize themselves in a particular, symmetrical physical arrangement. It’s a bit like the sight of soldiers on formal parade. We call the three-dimensional framework of ions a lattice, and it’s this regular pattern that makes the material crystalline; it is a crystal. In other words, the pieces of mineral in a vineyard are crystalline. We may think of crystals as having the attractive, light- catching facets seen in gem shops and museums. Although this is a manifestation of the crystalline structure of the constituent ions, it is not what defines them as crystals. Consequently, minerals lying in a vineyard may be dull, shapeless chunks, but they are still crystals.
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