Intricate Shapes: the Intriguing World of 19th Century Crystallography

Volunteer MUSA blogger, Anna Venturini writes about the development in the field of crystallography in the 19th century.

When I was a child, geology ranked third in the list of my strongest passions, right after astronomy and palaeontology. I used to collect any sort of crystals and minerals I could get hold of, especially during family holidays and trips. Although I ended up taking quite a different path, in my research I still happen to stumble upon crystals every now and then, as if it was some kind of destiny.

Until the Enlightenment, it was widely believed crystals were some variety of ice. In reality, crystals are constellations of atoms arranged in intricate microscopic structures which determine their outward shape, visible to the naked eye. Their complexity varies greatly, ranging from rather simple solids with three or four faces, to bewildering specimens featuring more than twenty facets and angles.

Fig. 1
Fig 1. A cut and polished geode. Who did not use to have one sitting on their desk?
©John Kaprielian / Photo Researchers / Universal Images Group / Rights Managed / For Education Use Only   

How to unravel such an off-putting complexity and investigate these amazing creations of nature? Nowadays, modern crystallography students are fortunate to rely on sophisticated 3D-printed models, interactive PDF files and digital viewing programs that allow live interaction with and manipulation of virtual crystals on a touch screen, or even through mobile apps such as Quiztallography

Such contemporary developments are the offspring of the scientific breakthrough which came in 1912 with the discovery of X-ray diffraction, a physical phenomenon allowing to determine a crystal’s molecular structure.

Fig. 2
Fig 2. Romé de l’Isle, Crystal model, terra cotta, c. 1780, Teylers Museum, Haarlem.
From Wikimedia Commons (Creative Commons Licence)

Before 1912, crystallography had already become an extensive and well-practised science, mainly drawing upon the expertise of keen geologists and mineralogists. However, back then the average crystallography student could only rely on the so-called ‘polyhedra’, idealised crystal models with equally developed facets that first saw the light in the late 18th century. After Jean Baptiste Louis Romé de l’Isle’s first amateurish specimens, made of terra cotta (Fig. 2), the scene was quickly taken over by René Just Haüy’s pear-wood models, which had the advantage of being much more accurate and long-lasting.

Fig. 3
Fig 3. Ambroise Tardieu, Portrait of René Juste Haüy (1743-1822), engraving. ©Private Collection /Look and Learn/ Elgar Collection / Bridgeman Images / Rights Managed

Resorting to the exquisite skills of some amongst the best French ébénistes, within a few years Haüy was able to set up an almost industrial production of finely-carved wooden crystal models, larger in size than Romé’s ones and widely praised for their aesthetic qualities. Collections of his models were shipped far and wide across Europe, achieving outstanding popularity as both objects of curiosity and teaching tools in secondary schools and universities.

Fig. 4
Fig 4. René Juste Haüy, Box of crystal models, 1770-1859, © MUSA, University of St Andrews

Interestingly enough, a box of Haüy’s wooden crystals is featured in MUSA’s collections (Fig. 4), together with a number of other coloured models (of unknown manufacture) that tell the fascinating story of the evolution of crystallography teaching in the 19th century (Fig. 5). Like all Haüy’s models, these must have been fairly expensive and not so easy to order, given the limited communication and shipping facilities available at that time. Most likely used for teaching purposes at the University, they are meant to illustrate Haüy’s theory, according to which the outward appearance of crystals (their facets) perfectly mirrored their hidden internal structure. Despite the wealth of digital technologies available today, similar models – made of wood, but also, surprisingly, of orthodontic impression plaster! – are still used by lecturers in the School of Earth & Environmental Science to teach students how to recognise and classify different types of crystals. In fact, informed research by W. Saeijs has demonstrated how Haüy’s models can actually be used to identify at least some the mineral species from which the idealised shapes were derived.

Fig. 5
5. Coloured wooden crystal models, 19th century, MUSA, St Andrews.
© Photo : Author

Haüy’s wooden models stand as testimonies of the French golden age in crystallography : in fact, by the 1830s, the lead had already passed to Germany, whose scientists would gradually pave the way for modern mineralogy and whose factories were to monopolise the production and commerce of crystal models as well.

If this blog post has roused your curiosity about crystals, keep your eyes peeled for an upcoming crystallography-themed display in the School of Art History’s Foyer : there will be plenty to learn about old-school crystallography and a selection of amazing objects from MUSA to see!

About Anna Venturini

Anna is a postgraduate student of Museum and Gallery Studies from Venice, Italy. Although she has a background in Italian Literature and Renaissance Art History, her personal and academic interests are manifold. A born magpie, she is particularly passionate about material culture and the decorative arts, with a special taste for antique furniture and obviously, jewellery.    

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