'We have had four generations of families in my shop - the grandmother, mother, daughter and baby,' said Patti Ho, managing director of Adler Jewellery.

Adler, a Swiss-based firm founded in 1886 and known for its high-quality European-style jewellery, has had a presence in Hong Kong for nearly 25 years. Prices start at HK$10,000 for a modest ring and can rise to eight digits for a sumptuous diamond necklace.

Before settling on a jeweller, Ms Ho urged people to shop around and compare different places.

'The most important thing is to find someone you can trust and who has a good reputation. A jeweller has to know how to choose good jewellery for a client. If someone doesn't know what they want, we will give them advice,' she said.

'But if someone tries on a necklace or a pair of earrings and it doesn't suit her, I never say it looks good. You have to be honest and make sure the client leaves with jewellery that they are happy with. You can't just push to make a sale because next time they won't come back.'

All of the jewellery sold by Adler is guaranteed and certified by international gemological laboratories.

Ms Ho makes it her business to get to know her clients and understand what design styles and gemstones they like. She keeps on top of the latest fashion trends and travels worldwide to meet designers. Long-term clients get special privileges when new merchandise arrives that might suit their fancy. 'When we have some new inventory in Hong Kong we call our old customers first,' she said.

Clients whose lifetime purchases have totalled more than HK$1 million are also eligible for a special discount.

Ms Ho likes to create a sociable atmosphere among her regulars by inviting them to group lunches or teas where everyone can get to know one another.

'We might have five to 10 people or 100 people. We just get together to talk about our families and our lives.'

In a similar vein, Hong Kong Universal Jewellery has been outfitting generations of Asia's well-heeled families for more than 40 years with fine diamond and coloured gemstone jewellery.

Co-owners Lydia Kwan and Kwan Ling are in charge of the Hong Kong operation of their father's jewellery business.

'Credibility is very important, with suppliers and with clients,' Kwan Ling said.

Word-of-mouth recommendations from friends were a good way of finding a reputable jeweller, she said.

Dealing with differing client tastes across the generations usually presents no problem. 'Even if a woman is 80 years old, they accept young-looking jewellery. They let their daughter wear their jewellery and the granddaughter will wear it too,' Ms Kwan said.

Universal typically caters for clients from age 30 and up, with jewellery priced from HK$10,000 to millions of dollars.

Long-term clients of the company know they can come by to chat and relax with a cup of tea or wonton noodles.

'They don't have to buy anything. They can sit and try on jewellery if they like. I enjoy it when old customers come in because we know each other and have fun,' she said.

Each appreciates honesty from the other. Ms Kwan recalled one instance where a small diamond that had popped out of a client's tweezers couldn't be found anywhere in the shop. Later at home, the woman found the diamond and she dutifully brought it back.

'This is the kind of relationship we have with our clients,' Ms Kwan said.

Jonathan Abram, a director of Ronald Abram, said choosing the right jeweller was more important than choosing gems. 'Because of the high value of jewels, jewellers can also be financial advisers and help their clients buy and sell at the right time. Jewellers can also take the gems and set them into beautiful pieces of jewellery. Also, in some cases, buying from certain jewellers adds a premium to the pieces of jewellery when one looks to resell.'

Mr Abram said the firm was a family business spanning three generations specialising in rare diamonds, emeralds, rubies and sapphires. He said customers were seldom one-time clients, and that honesty and professionalism were required to establish a long-term relationship between a jeweller and client. 'My father always reminds our clients that just like a good lawyer and doctor, you need a good jeweller to provide you with professional service and advise you.'