Sharp Island

Sharp Island or Kiu Tsui Chau () is the largest island in the Kiu Tsui Country Park located at Port Shelter of Sai Kung, Hong Kong. The area is most known for fishing, swimming as well as diving. Sharp Island is under the administration of Sai Kung District.
Geography.
The island has a maximum elevation of 136m and an area of 1 km². The two beaches, Half Moon Bay Beach (, also known as Hap Mun Bay), and Kiu Tsui Beach () are located on the island. Both are managed by the Hong Kong Leisure and Cultural Services Department.
When the predicted tides at Ko Lau Wan is lower than or equal to +1.40 meters, visitors are able to visit Kiu Tsui (), an inshore islet, on foot.
Different kind of volcanic rocks can be found on Sharp Island. The most frequent ones are rocks with a peculiar pattern on the surface. Other rocks have an unusual pineapple-shaped form.
History.
Origin of the different kinds or rocks.
It is believed that about 140 million years ago a volcano was located in Sai Kung. Sharp Island was according to that on the margin of the caldera. This is probably the reason for the widely distributed different volcanic rocks from different geological periods around Sharp Island.
Formation of the tombolo.
The sea currents near Sharp Island are pushing sand and gravel near the shore. After several years they formed a tombolo, a natural bridge made of different sized rocks and sand – connecting Sharp Island and Kiu Tau (). At high tide the tombolo is submerged in water and thus can only be seen when the tide goes out.
Biography.
There are over 70% of stony corals coverage around the island. An endangered flora Tetrathyrium subcordatum is found on the south of the island.