Some of the most interesting stuff at the crystallisation conference in Maine last week, was on trying to understand how living organisms control crystallisation. Many living organisms, including us, need tough strong structures and many crystals are strong, and much harder than living cells which are soft and squidgy. So many organisms have evolved to produce crystals, often in incredibly well organised ways. Our bones are based on a crystalline form of calcium phosphate, and many other organisms make structures out of crystalline calcium carbonate. At the top left is the calcium carbonate “armour” of a single celled plant called Emiliani huxleyi.

I find these arrangements of calcium carbonate plates in this tiny plant just amazing. To me it looks like something out of science fiction, but there are countless billions of these things floating in the world’s oceans. They are small, only around one hundreth of a millimetre across so they are too small to be seen with the naked eye.

To get a feel for what level of control Emiliani huxleyi has over crystallisation, this is what a calcium carbonate crystal looks like if it just grows without help from a living organism:

Rather different. We have a very poor understanding of how living organisms, including our own bodies, actually do this.

Incidentally, the unusual name of this species, Emiliani huxleyi, comes from the names of two scientists, one of which is Thomas Huxley, the self-taught 19th century scientist perhaps best known for his defence of Darwin’s theory of evolution in a famous exchange with the Bishop of Oxford.