The smiley face is a simple design: a circle with two oval eyes and a wide upturned mouth. And, this year, it has turned 50 — an anniversary marked by an Assouline book, Smiley: 50 Years of Good News by Liam Aldous, charting its evolution. It has put a smile on the face of jewellers, too — as reinterpreting this symbol of happiness, first used in a French newspaper to highlight good news, is proving a valuable driver of business.

“Everyone wants something that’s joyful and positive,” says Hollie Harding, a buying manager at multi-brand boutique Browns, which had a waiting list for a yellow enamel charm by Lauren Rubinski earlier this summer.

Coming out of Covid lockdowns, “people are feeling a lot more experimental, a lot more creative; they want that conversation piece as well, as they are seeing more people”, explains Harding. So, “something with a smiley face on it is definitely interesting compared to a plainer item — and it’s just that talking point”, she says.

London jewellery designer Roxanne First has seen sales of her 15 diamond and sapphire smiley face pieces increase by 25 per cent in the past six months and contribute 10 per cent to her 2021 revenue. First has used smiley face jewellery in her collections since her 2018 debut.

Annoushka Ducas, another London-based jewellery designer, says her first two smiley face necklaces, introduced this year,…