It is a seaside treat that families have got their teeth stuck into for more than a century in Great Yarmouth.
Sticks of rock have been a part of the bucket and spade experience for generations at the resort.
And now children and adults who can not resist the lure of the sugary sweets will be pleased to know that the seaside tradition is in safe hands yet again.
William Docwra is entering its 120th year of churning out the sweet treat, and little has changed in the production process.
In its 1950s and 60s heydays, the Great Yarmouth factory, which had 140 workers, was making 120,000 sticks of rock for resorts across East Anglia and other parts of the UK.
It now produces 25,000 sticks a week from its Regent Road site, but – much like the resort itself - is enjoying a longer season thanks to other year-round markets including weddings and corporate work.
Crowds gather in the shop to watch the cocktail of sugar and glucose transformed into colourful sweet souvenirs.
Stephen Docwra, the company's salesman and fudge-maker and grandson of its founder, said: 'People love to see the mystery of how rock is made, especially adding the message through the middle – a skill which can take years to master.
'Some come back every year and the staff know them by name. They love the nostalgia of seaside treats from their own childhood.
'Rock's enduring appeal is that is still a fun pocket money-priced treat and souvenir.
'People still say to holidaymakers 'bring us back a stick of rock'.'
The Docwra family's rock making - and connection with the resort's soon-to-be rejuvenated Venetian Waterways which was the idea of William Docwra - is featured in a behind the scenes video made by the Greater Yarmouth Tourist and Business Improvement Association to help promote the area.
GYTABIA chairman Gareth Brown said: 'Our videos aim to raise the profile of the area, but also show there is more to our tourism than meets the eye – helped by many dedicated, independent family businesses.'
It can be seen in the Explore (Regent Road) section at www.great-yarmouth.co.uk
The birth of lettered seaside rock is lost in Victorian history, but it may have been created by a man called Dynamite Dick, based on fairground treats.
In 1956 Docwra moved its rock and sweet factory from Middlegate to South Denes, which closed in 1985.
The Regent Road factory shop opened in 1922.
Great Yarmouth rock was sold by Woolworth stores in coastal towns across the UK and was a corporate marketing 'sweetener' for clients including Birds Eye, BBC and the Electoral Commission.
There were five rock factories in Great Yarmouth and now there are just a handful in the country. Docwra is owned by national company John Bull whose main factory is at Bridlington.
Making rock involves a two-to-one mix of sugar and glucose boiled to nearly 150 degrees then poured on to water-cooled steel plates. Coloured elements are created using food colouring.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here