
Grima became the foremost modern jewellery designer in the West End of London in the 1960s and 1970s, selling designs from his exclusive gallery in Jermyn Street, Mayfair. His clientele included celebrities and royalty, and his skill was recognised with several awards including being the only jeweller to have been awarded the Duke of Edinburgh's Prize for Elegant Design and his contribution to British exports was recognised with The Queen’s Award to Industry in its inaugural year. He won the De Beers Diamonds International Award (the Oscars of jewellery design) a record 11 times and, in 1969, was commissioned by Omega to create one of the most outrageous and daring watch collections ever made.
Grima was particularly interested in the organic possibilities of jewellery design and created pieces resembling objects found in nature; a piece of lichen sent to him by HRH Princess Margaret, was cast in yellow gold, offset with brilliant-cut diamonds and transformed into a brooch.