Diamond Rock Diamond Rock ( " Rocher du Diamant " ) is a 175 m ( 574 feet ) high basalt island located south of Fort - de - France , the main port of the Caribbean island of Martinique . The uninhabited island is about from Pointe Diamant . The island gets its name from the reflections that its sides cast at certain hours of the day , which evoke images of a precious stone . Its claim to fame is the role that it played in the Napoleonic Wars . HMS " Diamond Rock " . The Rock occupies a strategic position at the north end of the St . Lucia Straits . Possession of the Rock permits interdiction of navigation between Martinique and its southern neighbour , St Lucia . In September 1803 Commodore Sir Samuel Hood sailed to the Rock aboard ( Captain Murray Maxwell ) . Hood had received the assignment to blockade the bays at Fort Royal and Saint Pierre , Martinique . " Centaur " was lying at anchor in Fort Royal Bay , Martinique , on the morning of 1 December when lookouts sighted a schooner with a sloop in tow about six miles off making for Saint Pierre . Hood sent his advice boat , the " Sarah " , after the sloop , and had Maxwell sail " Centaur " in pursuit of the schooner . After a pursuit of some 24 leagues , " Centaur " captured the schooner , which turned out to be the privateer " Ma Sophie " , out of Guadeloupe . She had a crew of 45 men , and was armed with eight guns , which she had jettison ed during the chase . Hood took " Ma Sophie " into service as a tender , charging her captain , Lieutenant William Donnett , with watching the channel between Diamond Rock and Martinique for enemy vessels . Donnett made frequent visits to the Rock to gather the thick , broad - leaved grass to be woven into sailors ' hats , and a spinach - like plant called callaloo , that when boiled and served daily , kept the crews of " Centaur " and " Ma Sophie " from scurvy and was a nice addition to a menu too long dominated by salt beef . Aided by surprise and by calm weather , the British were able to run lines ashore and hoist two 18 pounder cannon s to the summit of the Rock . The British hastily built fortifications and supplied the position with food and water for a garrison of two lieutenants and 120 men under the command of Lieutenant James Wilkes Maurice , Hood ' s First lieutenant . ( In a contemporary print of the main characters involved his name is spelt Morris . ) Hood officially commissioned the Royal Navy - garrisoned island as a sloop HMS " Diamond Rock " . A six - gun sloop , designated " Fort Diamond " , supported the fort . In honour of his Admiral , Maurice designated as " Hood Battery " the one 24 - pounder that he placed to fire from a cave halfway up the side of the Rock . The British also placed two 24 - pounder guns in batteries ( " Centaur " and " Queen ' s " ) at the base of the Rock , and a 24 - pounder carronade to cover the only landing - place . One account puts two 24 - pounders on the summit , but all other accounts put 18 - pounders there . Unfortunately , at some point while this was going on , " Ma Sophie " blew up for unknown reasons , killing all but one of her crew . With work complete by 7 February Hood decided to formalise the administration of the island , and wrote to the Admiralty , announcing that he had commissioned the rock as a sloop , under the name " Fort Diamond " . Lieutenant Maurice , who had impressed Hood with his efforts while establishing the position , was rewarded by being made commander . Caves on the Rock served as sleeping quarters for the men ; the officers used tents . A court martial would reprimand Lieutenant Roger Woolcombe at Plymouth on 7 December 1805 for " conduct unbecoming a gentleman " for having messed ( eaten ) at the top of the Rock with part of the ship ' s company . The troops used pulleys and ropes to raise supplies to the summit . To augment their uncertain food supply , the garrison had a small herd of goats and a flock of guinea hens and chickens that survived on the meager foliage . The British also established a hospital in a cave at the base of the Rock that became a popular place to put sailors and marines recovering from fevers or injuries . Just before " Centaur " left the Rock , a party of slaves made a clandestine visit at night to trade fruits and bananas . They brought the news that a French Lieutenant Colonel of Engineers had arrived at their plantation to survey the heights opposite for a mortar battery with which to shell the Rock . One of the slaves had been sold by his English owner to the French when the owner left the islands . He did not like his new master and claimed the protection of the British flag . Hood granted him that protection , and promised that the man could serve in the Royal Navy as a free man in return for guiding a landing party to his now former master ' s house . A 23 - man landing party , including the guide , and under Lieut . Reynolds , landed at midnight , walked the four kilometers to the plantation house , and took the engineer and 17 soldiers prisoner , before returning safely to " Centaur " . Apparently the Lieutenant Colonel was the only engineer on Martinique and so no mortar battery materialized . On June 23 , 1804 , whilst the " Fort Diamond " was on a provisioning expedition at Roseau Bay , St . Lucia , a French boarding party from a schooner came up to her in two rowboats , boarding her at night while most of the crew were asleep below decks . A subsequent court - martial aboard HMS " Galatea " at English Harbour , Antigua , convicted Acting Lt . Benjamin Westcott of allowing his vessel to be captured . The Board dismissed him from the Service , never to be permitted to serve in the Navy again . ( Three years later he became an American citizen . ) For 17 months the fort was able to harass French shipping trying to enter Fort - de - France . The guns on the Rock completely dominated the channel between it and the main island , and because of their elevation , were able to fire so far out sea as to force vessels to give it a wide berth , with the result that the currents and strong winds would make it impossible for them to fetch in Port Royal . During this time the French troops on Martinique made several unsuccessful attempts to retake the Rock . Capture . When Admiral Villeneuve embarked on his 1805 voyage to Martinique , he was under orders from Napoleon to recapture Diamond Rock . The French - Spanish combined naval force of sixteen ships under French Captain Cosmao - Kerjulien attacked Diamond Rock . Between 16 May and 29 May , the French fleet completely blockaded the Rock . On the 25th , the French were able to cut out from under Maurice ' s guns a British sloop that arrived from St . Lucia with some supplies . The actual assault came on 31 May and the French were able to land some troops on the Rock . Maurice had anticipated the landing and had moved his men from the indefensible lower works to positions further up , and on the summit . Once the French landed , British fire trapped the landing party in two caves near sea level . Unfortunately for the garrison , their stone cistern had cracked , due to an earth tremor , so they were short of water , and after exchanging fire with the French , they were also almost out of ammunition . After enduring a fierce bombardment , Maurice surrendered to the superior force on 3 June 1805 , having resisted two French seventy - fours , a frigate , a corvette , a schooner , and eleven gunboats . The British lost two men killed and one wounded , and the French 20 dead and 40 wounded ( English account ) , or 50 dead and wounded ( French account ) , and three gunboats . The French took the garrison of 107 men as prisoners , splitting them between their two 74 - gun ships of the line , " Pluton " and the ex - British " Berwick " . The French repatriated the prisoners to Barbados by 6 June . The subsequent court - martial of Commander Maurice for the loss of his ship , i . e . , the fort , exonerated him , his officers , and men and commended him for his defence . Maurice took dispatches to England , where he arrived on 3 August , and was given command of the brig - sloop . The Battle of Diamond Rock in literature . There is a now obscure poem of some forty four - line stanzas based on the incident , titled " The Diamond Rock " . The author " Sea Lion " ( the Pseudonym of Geoffrey Bennett , a career naval officer ) , based his 1950 novel " The Diamond Rock " on the 1804 event . So did Dudley Pope in his 1976 novel " Ramage ' s Diamond " . The British Royal Navy still regards " HMS Diamond Rock " as being in commission . Therefore , Royal navy ships are required , when passing , to show due respect , personnel on the upper deck to stand at attention and face the Rock whilst the bridge salutes . Natural history . The rock is a volcanic plug , a remnant of the strong volcanic activity that affected the region some one million years ago . However , a Captain Hansen of the Norwegian steamship " Talisman " reported that on 13 May 1902 , he observed what he took to be a volcanic eruption from a hole in the rock . This was at the time of the devastating volcanic eruption of Mount Pelée that destroyed Saint - Pierre . Hansen did not investigate further . Like the other 47 islets that circle Martinique , the Rock has its own ecological characteristics . It is sunnier than the main island , drier , and subject to a long seasonal dry period . Today it is covered in undergrowth and cacti . Relatively inaccessible and inhospitable , the island is uninhabited , which has permitted it to remain a sanctuary for a species that had been believed to be extinct . A nature survey has suggested that Diamond Rock is probably the last refuge for a species of reptile once endemic to Martinique , the Couress grass snake ( " Liophis cursor " ) . This snake was last seen on Martinique in 1962 and has not been encountered since then . It is now considered to be extinct . Diving the Rock . Below water the Diamond Rock cavern , a deep triangular cave , is a popular attraction for scuba divers . The cave is said to contain prolific quantities of beautiful sea fan s and corals , though strong current s make diving the island a risky venture . The author John Fine reports that while diving he found one of the Rock ' s cannon that the French had toppled from the summit . References . geology