Friday, February 24, 2006

Goethite



Everything is simpler than you think and at the same time more complex than you imagine

Johann Wolfgang von Goethe

A couple of weeks ago I happened to switch the TV on late at night and discovered a fantastic film by Murnau called Faust which is based on the poetic drama of the same name by Johann Wolfgang von Goethe. It is an angst-ridden film, washed by shadow, in which Faust is tempted by Mephistopholes into sinning. It got me thinking about Goethe and the mineral named after him called Goethite.

I first encountered the mineral Goethite when I was studying the Lower Greensand, a geological formation of southern England deposited during the Cretaceous period some 100 million years ago. The last phase of deposition of the Lower Greensand consists of red coloured sands which form a thin bed (usually no more than a few metres thick) which is extemely extensive, probably originally covering most of south-east England.

The sands get their red colour from tiny red-brown grains called Goethite ooids contained within them. Ooids are sediment grains that form by mineral accretion on the sea floor. They are most commonly formed from white calcium carbonate, especially in warm tropical seas such as the Bahamas where the famous white beaches are made out of ooidal sands. Goethite ooids are rarer today and form by the accretion of iron minerals on the sea floor, rather than calcium carbonate.

When I first read about Goethite ooids, I failed to make the connection with the poet Goethe, although I knew of him. I suppose the two things seemed too far apart. With age, however, everything begins to connect.

Goethite is the only mineral named after a poet. Here are some orgins of other mineral names.

Goethite doesn't just form ooids. It is also precipitated from heated waters carrying iron in solution underground. The crystals so formed are polymorphous: that is to say they have a wide range of crystal forms. One of them is this massive, mamillated form shown in the photograph below. Rather suggestive, no?



It puts me in mind of some of the figures sculpted by Rodin.



Another form are these bullet-shaped crystals.



I think crystal structures have often been an inspiration for architects of high rise offices such as the one below.


La Defense
Originally uploaded by Grébert.

I wish Goethe could see this. I wish he could walk around inside, along the corridors set at any angle except ninety degrees, a feature that is disorientating for the first year or two.

One is transformed by stepping inside this giant crystal which seethes with the energy of global communication. It is like a great black lightning rod summoning information and disparate souls from all over the planet.

And I wish I could show Goethe my lump of goethite. The one at the top of the page. He would have been interested I know. He used to collect minerals. Russian princes sent him platignum from their mines to show their appreciation of his work. This piece of goethite is a concretion. It is very large, very heavy and hollow like a cocoanut. When you shake it, it rattles, because inside it is crumbling, dessicated.

Because I've broken open other smaller concretions, I know that, inside, this one has a blackened pearly sheen like an evil oyster. I'll never crack it open though. It makes more sense to me whole. A sort of Pandora's box.

Here is another polymorph of goethite: acicular, needle crystals. How different they are to the mamillary forms above. The antithesis. One can imagine trying to inject one kind into the other.



These needles cluster together and form sea urchins like those I once saw making their way across the sandy floor of a Greek bay after a storm. Poisonous, I'm sure. When I went swimming, I was always careful where I put my feet down.



I'd like too know more about the way Goethe thought about science. Here is the blurb from "Goethe's Way of Science" by David Seamon and Arthur Zajonc, published by the State University of New York Press in 1998.

Though best known for his superlative poetry and plays, Johann Wolfgang von Goethe (1749-1832) also produced a sizable body of scientific work that focused on such diverse topics as plants, color, clouds, weather, and geology. Goethe's way of science is highly unusual because it seeks to draw together the intuitive awareness of art with the rigorous observation and thinking of science.

Written by major scholars and practitioners of Goethean science today, this book considers the philosophical foundations of Goethe's approach and applies the method to the real world of nature, including studies of plants, animals, and the movement of water. Part I discusses the philosophical foundations of the approach and clarifies its epistemology and methodology; Part II applies the method to the real world of nature; and Part III examines the future of Goethean science and emphasizes its great value for better understanding and caring for the natural environment.

5 comments:

Patry Francis said...

An apparently effortless combination of poetry and science. Thank you for this.

Da said...

Loved reading about "Goethite". Bought back a piece of "dessert rose" from Sahara for your nephew. Can you give an me an explanation of how it was formed?

Jonathan said...

Thank you both for your comments. I have posted a small poem about desert roses for you Da.

Ivy said...

Jonathan, what a great post. I loved learning about goethite.

Jonathan said...

Thank you Ivy.