Looking at this lovely selection of selection of diamond engagement rings (above) from Tiffany & Co makes me wonder why I didn't choose a diamond engagement ring. Mine is a wide yellow gold band set with pink sapphires in a design inspired by an ancient Visigoth crown. Not exactly your traditional diamond solitaire. Bought in one of Madrid's most traditional jewellery shops, the sales staff were put out by my choice and insisted on trying to change my mind. In hindsight it may have been more sensible to go for a classic all white diamond ring as I can't wear my very pink sapphires with red shoes: a key consideration that slipped my young mind as I gazed into those candy-bright sapphires. If you are going for a straight-up, can't-go-wrong diamond solitaire consider carefully the cut . Yes I know we have all heard of the Four 'C''s (cut, carat, colour and clarity) but do bear in mind the shape of a diamond can really change the look of the ring. Carats, clarity and colour are more technical jargon to make you feel like you actually know what you are doing and invented by the diamond industry to help us embrace the culture of diamonds. The only person who knows how to chose a diamond is a professional grader who factors in some 12,000 variants when grading a stone. Choose a cut you like and budget will dictate the rest. My favourite is the emerald cut, which as its name suggests is cut in the shape most often used for emeralds. For the non plus ultra of this cut, see Harry Winston's impeccable ring set in minimalist platinum with additional diamonds niftly tucked-into the shank, playing second fiddle to the big daddy in the middle. This ring is the stuff of dreams and in the "could buy a flat" for that price bracket. As well as making me sigh every time I look into its glacial depths, it also serves to illustrate the elegance of the emerald cut. Less brash in its fire than a round or brilliant cut, the long smooth planes eloquently suggest its value without looking 'bling.' Other unusual cuts to consider are the marquise or pear, both of which are variants on a tear drop shape and sit prettily on the hand, flattering the length of the finger. I have chosen a few other rings to show the breadth of design available today. I would happily wear any of these all life long. Will they go out of fashion, perhaps, but I think that choosing something that captures the mood of your times adds a special touch to your choice and will always remind you of what was going on when you chose it. Take Astley Clarke adorable Forget Me Not ring at £4,495 available on line. I can hear the sound track playing already and feel the sun on my face. Vuitton has been growing its collection of jewels and includes the Les Ardentes diamond ring, that with its flower shaped diamonds stands out from the crowd. British jewellery house Boodles suggests an alternative in the form of a rose with a sizable diamond in the centre for a soft, romantic look. Chaumet's Tiara looks like a little head ornament shrunk down to fit finger. Easier to wear than a tiara for those with regal aspirations or who like a dash of historical references in their jewels. I have chosen Damiani's deceptively simple solitaire ring as it is a very good example of how the most simple design if beautifully conceived and made can be very special. Note the tapered curves that swoop up towards the stone. Little details that you will have many years to appreciate. But whatever style you chose, always buy from a reputable source. And by reputable I mean a jeweller that would have something to lose if found selling diamonds from dubious sources. Ask to see a Kimberley Certificate for the batch that the diamond came from and please chose jewellers that are members of CRJP (Council for Responsible Jewellery Practices).