Colour is a key trend in luxury jewellers' latest collections, with the use of yellow gold and diamonds emerging as a dominant influence. 'Colours have been more pivotal in fashion in recent years with gold playing a crucial part,' according to Italian jeweller Bulgari. 'Yellow gold is the perfect metal for warm tones, as well as coloured precious stones or diamonds.' Its latest Astrale collection features necklaces, rings and earrings in 18-carat yellow gold with coloured gemstones and pave diamonds. The collection plays on the combination of circular motifs with the end design elegant and innovative. 'Customers today look for designs that are of top quality and distinguished design,' Bulgari says. 'The Astrale collection represents the best of both.' Tiffany & Co has launched a new collection featuring rare fancy yellow diamonds, with the company's own stonecutters tailoring the Tiffany Diamond's cushion cut to maximise the stones' natural colour in a modern setting. The Tiffany Bezet, a contoured ring design based on the traditional bezel setting, features hand-set yellow diamonds of pear, heart, oval and cushion shapes in 18-carat gold. In another collection, Elsa Peretti's designs for Tiffany & Co, there is the launch of a pear-shaped yellow diamond pendant in platinum or 18-carat yellow gold. The sourcing of yellow diamonds at Tiffany & Co has become so important that the jeweller has entered into an exclusive agreement with Gem Diamonds' Ellendale mine in Western Australia, giving the New York jeweller exclusive rights to the renowned mine's production of fancy yellow diamonds over its full economic life. 'This agreement gives us a unique opportunity to extend our diamond authority with exceedingly rare fancy yellow diamonds,' says Jon King, the company's executive vice-president. 'The collection underscores our design heritage with settings that fully reveal the stones' natural beauty and warm yellow colour.' Only about one in 10,000 diamonds is a fancy colour, and few meet Tiffany & Co's high standards, the company explains. 'Those that do have a deep enough natural colour to qualify as a fine, fancy colour diamond are the rarest of the rare,' it says. At the Tiffany Gemological Laboratory, the jewellers' fancy colour diamonds are assigned colour grades based on three criteria of hue, the basic body colour, tone, the lightness or darkness of the hue and saturation, the purity of the hue, and the amount and quality of modifying shades. Other natural properties taken into account include the brilliance and fire combined with such hues as yellow, pink, blue, green and even orange to create a vibrancy few other gemstones possess. Cartier has used antique jade and lavender, black and green jades, alongside diamonds, to create its latest contemporary collection. 'Cartier mixes gemstones and diamonds, eras and inspirations, to create jewels and objects that lie on the trajectory between China and Paris,' says Tamie Toledano, Cartier's Far East marketing and communications director. 'Cartier imbues works with a pure modern clarity, such as rings and earrings that contrast jade with the facets of diamonds.' The latest collection, which combines traditional Chinese elements and the heritage of Cartier, is expected to attract the attention of the Chinese consumer and the Asia-Pacific market. 'This collaboration results in elegant creations our Asian clientele can have a personal connection to and, in a way, feel like they are acquiring something that is exclusively made for them,' Toledano says. Cartier first incorporated jade into its production in the early 20th century with its most well-known jade pieces - the cabochon ring and the spectacular bead necklace created for American heiress Barbara Hutton. It is Hutton's ring that has inspired the look for the imperial jade cabochon ring.