His famous black and white halved colours have been carried with distinction at the highest level, with horses like the 1982 1,000 Guineas winner On the House and the 1987 Derby runner-up Most Welcome, both of which he bred.
But Oppenheimer's contribution to racing ended not just with his own horses. He played a significant part in the advancement of sponsorship, without which the sport would struggle to survive today.
His family's diamond company De Beers had a huge effect on racing with its long-standing sponsorship of the King George VI and Queen Elizabeth Diamond Stakes at Ascot, among the top races in the world. That sponsorship started in 1972, and Philip Oppenheimer won his "own" race in 1978 with the victory of Ile de Bourbon, in which he owned a share. The colt also won the Coronation Cup a year later as a four-year-old.
Educated at Harrow and Cambridge, where he was a boxing blue, Oppenheimer was a member of the famous Anglo-South African diamond family. He joined the company in 1934, starting in the Central Selling Organisation, learning the intricacies of sorting and valuing rough diamonds, first in London, then in Antwerp.
He served on the board of De Beers from 1956 and as chairman of one of its branches, the Diamond Trading Company, from 1975, during a particularly difficult time for the company, and it is to his credit that it was not irreparably tarnished by association with apartheid.
Despite having briefly ridden as an amateur rider, Oppenheimer did not start to own horses until his late forties. His first winner was Little Redskin in 1959.
Six years later he made a significant purchase, the Hascombe Stud in Newmarket, which he merged with his own Valiant Stud, named after his children Valerie and Anthony. It was from here that most of his top winners were bred.
Many of them descend from one of his first brood mare purchases, Stop Your Tickling. She produced Miba, who won two top races for fillies in 1965, the Princess Elizabeth and Pretty Polly Stakes. She in turn was dam of African Dancer, third to Pawneese in the 1976 Oaks.
African Dancer produced the good handicapper On Show, herself dam of the leading juvenile Welney, and his half-sister Inchmurrin, winner of the Child Stakes and dam of Inchinor, a leading miler during the 1993 season.
Oppenheimer achieved the ambition of any owner in winning a Classic, the 1982 1,000 Guineas, with On the House, which was also third in the Irish equivalent and beat the colts and the older generation in the Sussex Stakes at Goodwood. At the same Goodwood meeting, another Oppenheimer filly, Dancing Rocks, beat that year's Oaks winner Time Charter in the Nassau Stakes.
When Oppenheimer did buy racehorses, rather than breed his own, the purchases were often shrewd. One example was the Derby runner-up Most Welcome, whose form had tapered off by the time Oppenheimer bought him in 1988. He went on to be placed in the Turf Classic at Belmont Park, one of America's top turf races, and beat a field of outstanding milers as a five-year- old in the 1989 Lockinge Stakes at Newbury.
Oppenheimer, who was elected to the Jockey Club in 1971, shared his racing interests with his son Anthony, who also became a director of De Beers.
They had about 20 brood mares at Hascombe, and although they raced most of their produce, some were sold as yearlings and some after their racing careers. He was fortunate that neither Pelerin nor On the House fetched their reserves when offered for public auction as yearlings, as both went on to great successes. Pelerin was fourth in the Derby in 1980 and won several top races as a four-year-old in 1981.
One of his potentially best fillies, Sally Rous, was killed in November 1990 on a return flight from New York where she had finished second in the Budweiser Breeders' Cup. There was more bad luck five months later when the promising colt, Welney, died after fracturing his pelvis on the gallops.
Philip Jack Oppenheimer, diamond dealer and racehorse owner: born London 29 October 1916; Director, De Beers Consolidated Mines and De Beers Centenary AG 1956-95; chairman, Diamond Trading Company 1975-95; Kt 1970; married 1935 Pamela Fenn Stirling (one son, one daughter); died London 8 October 1995.