In the last section of the gemstone guide, we introduced the notion of coloured gemstones and diamonds. Now we start to look at the differences between them. While coloured stones have been used extensively throughout history, in recent decades gemstone sales have shifted towards colourless diamonds or "white" diamonds. This drastic change of direction was due to a very clever marketing campaign by De Beers in 1948 entitled "A Diamond is Forever".

De Beers "Diamond is Forever" campaign in 1948, Source: De Beers

As De Beers at that time controlled the world's diamond supply and those diamonds were white, the marketing campaign was centred around those white diamonds. In subsequent years this campaign remained so strong, that there are many people today that don't realise that diamonds come in colours other than white.

But let's not vilify De Beers completely, it was after all they who turned the diamond into a symbol of love and romance, and the diamond engagement ring, even though the concept has been around since medieval times, was also made hugely popular through this campaign. And, as engagement rings are the cornerstone to many a jeweller's bottom line, we can only thank De Beers for their contribution. Together with the invention of the Rapaport price guide to white diamonds and the stranglehold the GIA have over diamond certification, the selling of white diamonds has become as easy as ABC. This has also led to the decimation of profits on sales.

However, as a consequence people no longer understand the value and intricacies of appreciating coloured gemstones. But times are changing and more and more people are asking to have rubies, sapphires and emeralds in their engagement rings. Perhaps due to the trend of vintage jewellery where the use of coloured gemstones are the norm, or perhaps it is due to the glitterati donning the latest top end jewellery designs, which have historically used coloured diamonds and gemstones in their jewellery designs.

The resurgence may even be down to the likes of Heidi Klum, Kelly Clarkson, singer Adele and Jennifer Anniston choosing yellow diamonds for their engagement rings. In royalty most recently Catherine, Duchess of Cambridge's engagement ring being a 12-carat oval blue Ceylon sapphire. Whatever the reason, fancy coloured diamonds and gemstones are back in vogue and certainly look to stay that way.

So the demand is there already, it just needs to be tapped into by you, the jewellery designer or jewellery seller.

The first step in marketing and promoting coloured gemstones stones and natural coloured diamonds needs to be creating an understanding of how these stones should be valued.

Being able to quickly and succinctly explain the value of these points will give your customer confidence in your gemstone knowledge and may win you a sale.