The keepsake had belonged to William Waldegrave, 1st Baron Radstock (1753-1825), who served with Nelson at the Battle of Cape St Vincent in 1797.
The brooch is engraved to the reverse 'Lord Nelson’s Hair’.
Last week a cabinet made of wood from Nelson’s flagship made 13-times estimate.
Auction house Michael Bowman in Devon sold a bookcase made with wood salvaged from HMS Foudroyant, which served as Nelson’s flagship in the Mediterranean Squadron.
It sold at a hammer price of £41,000 on September 24 (plus 17.5% buyer’s premium).