12 Baylis Mews, Amyand Park Road, Twickenham, Middlesex, TW1 3HQ, United Kingdom.

Tel: +44 (0)20 8891 6600
Fax: +44 (0)20 8891 6599
Email: info@minersoc.org

Registered Charity No. 233706
VAT Reg. No. GB 238 7676 17

Photo Gallery

Click on a photo to enlarge and for more information.

NAC Field trip 6
General
Smectite, variety hectorite
'Images of Clay'

EMU Notes in Mineralogy - volume 14

Minerals at the Nanoscale
(F. Nieto and K.J.T. Livi, editors)  

Chapter 5. Structure and microstructure of serpentine minerals
by Marcello Mellini

The basic serpentine structure is extremely simple. In spite of the simple crystalchemical features involving the nearest neighbours (namely, the coordination polyhedra), complexity arises because of the different ways in which the basic polyhedra assemble together, forming flat layers in lizardite, curled layers in chrysotile, alternating layers in antigorite, flat kinked layers in polygonal serpentine, and flat geodesically kinked layers in polyhedral serpentine.

Further complexity is derived from not-nearest-neighbour relations, such as polytypism and polysomatism, that may occur as ordered and disordered distributions. A peculiar feature of chrysotile and polygonal serpentine is the presence of local fivefold symmetry. Chrysotile shares many nanoscale properties with synthetic nanotubes and nanowires.
Serpentine minerals may be mutually associated, or interleaved with other layer silicates. Serpentinization and deserpentinization reactions have important implications for many extremely important large-scale processes occurring in the Earth’s crust and outer mantle.

Due to their occurrence as tiny disordered crystals, meaningful structural study of serpentine minerals deals mostly with the nanoscale and may require alternative, unconventional methods. For this reason, electron microscopy techniques have long been used widely in the study of serpentine minerals, revealing a fascinating microstructural world. 

Go to the table of contents for this book

Go to the Mineralogical Society's online shop to buy a copy of the book from which this chapter is taken