It is relatively easy to take acceptable photographs of mineral specimens.  Five years ago I photographed my Riemvasmaak fluorite collection for illustrations for an article published in Lapis magazine (Miller, D. 2010. Die Fluorite von Riemvasmaak, Südafrika – ein Besuch vor Ort. Lapis Mineralien Magazin April: 38-44).  These were taken with nothing more sophisticated than a cardboard box with cut-out windows covered with matt tracing paper in sunlight, and sloping black or white paper inserts for the backgrounds.  I used a small, automatic point-and-shoot camera with a macro setting.  
My attempts at photographing gemstones with this sort of set-up were not successful.  It needed more complicated lighting to bounce light into the front of the gemstone and the little camera could not get close enough to small stones.  Exploring on the web produced several sites showing variously more complicated illumination arrangements, but one of the simplest for photographing single stones was illustrated by Gary Braun (http://gemologyonline.com/Forum/phpBB2/viewtopic.php?f=57&t=6420).  So I tried to emulate Gary’s set-up with a Solux ‘true daylight’ globe, some muslin stolen from the kitchen as a diffuser, and a black storage box to cut out stray light.



Once the shot has been set up, with the stone in place and the camera focused manually, a piece of white cardboard with a 2 cm diameter hole in it is placed in front of the lens to reflect light into the front of the stone. (Photo above). Altering the position of the light and the tilt of this reflector even slightly can have a dramatic effect on the reflections from the stone.   When everything looks good on the camera monitor screen, the correct exposure is selected and the photograph taken.  It took me a while to learn how to operate the new digital SLR camera properly, and even longer to get to grips with arranging suitable illumination.  It is easy to produce a photograph in which the stone looks dead and also one in which individual facets are over-exposed and flare brightly. Fortunately, with a digital camera one doesn’t have to be economical with the shots, and you can take literally dozens of photographs to select only the best one afterwards when viewing them on the computer.

The photograph above is a 21,90 ct tourmaline I cut recently in Jeff Graham’s Utopia barion pear. The photograph is un-retouched and shows not only some surface dust spots, but also the pleochroism – green in one crystallographic direction and more blue in the other – as well as a few inclusions and subtle, internal lamellar variations in colour and refractive index. The gemstone is 15 mm wide.  Duncan Miller