Question: For what is the sand of the beach near where the sloop Nancy was launched in 1803 famous?

Context paragraphs:
Little Manly Beach: Little Manly Beach is a beach on Sydney Harbour, in Little Manly Cove, near Manly Cove in Manly.  Arthur Phillip was stabbed in the shoulder after interrupting some Australian Aborigines butchering a whale carcass near here.  There are some historic baths, and toilets, and known for a popular kiosk that is open for breakfast lunch and dinner through the daylight savings period.  There is also a beach in manly called manly beach near manly cove.

New Carissa: MV "New Carissa" was a freighter that ran aground on a beach near Coos Bay, Oregon, United States, during a storm in February 1999 and subsequently broke apart.  An attempt to tow the bow section of the ship out to sea failed when the tow line broke, and the bow was grounded again.  Eventually, the bow was successfully towed out to sea and sunk.  The stern section remained on the beach near Coos Bay.  Fuel on board the ship was burned off "in situ" with napalm, but a significant amount was also spilled from the wreckage, causing ecological damage to the coastline.

Papakolea Beach: Papakōlea Beach (also known as Green Sand Beach or Mahana Beach) is a green sand beach located near South Point, in the Kaʻ ū district of the island of Hawaiʻ i.  One of only four green sand beaches in the world, the others being Talofofo Beach, Guam; Punta Cormorant on Floreana Island in the Galapagos Islands; and Hornindalsvatnet, Norway.  It gets its distinctive coloring from olivine sand eroded out of the enclosing volcanic cone (tuff ring).

Jervis Bay: Jervis Bay ( or ) is a 102 km2 oceanic bay and village on the south coast of New South Wales, Australia, said to possess the whitest sand in the world.

Nancy (1803 ship): Nancy was a sloop launched in 1803 and wrecked on 18 April 1805 near Jervis Bay, Australia.

Nadezhda (1802 Russian ship): Nadezhda (or "Nadeshda", or "Nadeshada" ) was a three-masted sloop, the ex-British merchantman "Leander", launched in 1799.  Private Russian parties purchased her in 1802 for the first Russian circumnavigation of the world (1803-1806), and renamed her.  Although it is common to see references to the "frigate "Nadezhda"", she was a sloop, not a frigate, and she was never a warship.  After her voyage of exploration she served as a merchant vessel for her owner, the Russian-American Company, and was lost in 1808.

Cumbuco: Cumbuco is a small fishing village situated about 25 km North West from the city of Fortaleza, in the state of Ceara, along the north east coast of Brazil.  The population is around 1600.  The village is regarded as picturesque and scenic and is attracting both domestic and international tourism.  Cumbuco has a beautiful and quiet beach near Fortaleza on one side of town and the famous sand dunes on the other side.  There is a small and busy village centre built around the main square adjacent to the beach which has a fresh fish market, tropical palm trees, and several beach restaurants (barracas).

HMS Saltash (1741): HMS "Saltash" was an 8-gun two-masted sloop of the Royal Navy, built on speculation by Henry Bird at Deptford Wet Dock on the Thames River, England.  She was purchased while building by the Navy Board at the end of August 1741 to replace the 1732-built sloop of the same name (which was sold on 24 August).  The new sloop was launched on 3 September.

HMS Curlew (1803): HMS "Curlew" was the mercantile sloop "Leander", launched at South Shields in 1801.  The Royal Navy purchased her in 1803 and named her "Curlew" as there was already a  in service, and the "Curlew" name was available.  "Curlew" was a sloop of 16 guns.  The Navy sold her in 1810.

Booby's Bay: Booby's Bay is a sandy beach near Padstow, Cornwall, England, UK.  The beach is wide with many rock pools.  It is completely covered by high tide and is popular with surfers, though may be dangerous for the amateur.  There is a lifeguard on duty during the summer, but the water is often red-flagged.  Access to the beach is by climbing down from the coast path, or walking along the beach at low tide.  Dogs are allowed on the beach all year round.  Booby's Bay has no beach at the highest tides, the ribs of a wrecked ship appear periodically as the sand is relocated by the sea and prevailing currents.  During World War I the three masted sailing ship "Carl" of the German navy was beached and abandoned in Constantine Bay while being towed to London during a storm.

Supporting paragraphs: Nancy (1803 ship) Jervis Bay
Answer: the whitest sand in the world