The business was doing well "but we work very hard at what we do".
With son James he leaves on Monday for a gem-buying trip in Hong Kong.
"It is an international trade fair and there will be about 3500 exhibitors, so there is a huge resource to be tapped."
Buying their own diamonds was a point of difference "and we can provide better quality stones".
"After 30 years we like to think we know what we are doing."
Coming in third for the Supreme Award was Kilt Napier. The women's clothing chain is headquartered in Onekawa and its Napier store also won the Best Large Retailer Award and the Omnichannel Award for Large Retailers. Its New Plymouth store was runner-up in the Large Retail Award, its Dunedin store was runner-up in the Best Large Retailer Award and the Dunedin store was also highly commended for the Customer Experience Award.
Kilt was the 2015 Supreme Award winner of the Westpac Hawke's Bay Chamber of Commerce Business Awards.
Grieve Diamond Jeweller aslo won the Small Retailer Omnichannel Award.
Wallace Cotton in Napier won the national Visual Merchandising Award and Beaukayes Florist in Napier was highly commended for the Best Small Retailer Award.
The bi-annual awards were their 30th year and "all about celebrating success in the competitive world of retail", Mr Harford said.
"Across New Zealand, more than 209,000 people are employed across 27,000 retail businesses. Retail is increasingly diverse, and retailers increasingly need to be engaging across physical and online channels, and providing outstanding service, as well as great products and prices to be successful."