It was great to see a presentation of agate images from the website on http://geology.com/ this week and while browsing the home page I noticed a book I hadn’t come across before. Entitled A Grain of Sand it features extraordinary images by the author, Dr Gary Greenberg, taken with a 3D light microscope he developed and patented – you can find out more at his website http://www.sandgrains.com/.
It has been estimated that there are 48,000 billion billion grains of sand on earth and, true to the maxim that Nature never repeats herself, no two are exactly alike. But just how unalike is the real revelation of the book. Sand grains vary according to the rock they are derived from and the extent and nature of erosion they have undergone – the archetypal round grain of quartz is typically the product of several cycles of erosion over a billion years. Biological materials such as shells, diatoms and foraminifera also form a significant element in many sands, adding greatly to the microscopic variety of form and colour.
The centrepiece of the picture above looks like just the sort of thing I would like to scan. It’s made of chabazite, a glassy member of the zeolite family which, like many of the most beautiful minerals, are silica-based. The only snag is that this specimen is a mere 1/4mm across – not much larger than some of the specks of polishing powder I remove digitally as impurities! With Dr Greenberg’s book as stimulation, it is easy to join William Blake in imagining ‘a world in a grain of sand’.
It has been estimated that there are 48,000 billion billion grains of sand on earth and, true to the maxim that Nature never repeats herself, no two are exactly alike. But just how unalike is the real revelation of the book. Sand grains vary according to the rock they are derived from and the extent and nature of erosion they have undergone – the archetypal round grain of quartz is typically the product of several cycles of erosion over a billion years. Biological materials such as shells, diatoms and foraminifera also form a significant element in many sands, adding greatly to the microscopic variety of form and colour.
The centrepiece of the picture above looks like just the sort of thing I would like to scan. It’s made of chabazite, a glassy member of the zeolite family which, like many of the most beautiful minerals, are silica-based. The only snag is that this specimen is a mere 1/4mm across – not much larger than some of the specks of polishing powder I remove digitally as impurities! With Dr Greenberg’s book as stimulation, it is easy to join William Blake in imagining ‘a world in a grain of sand’.
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