Zabargad Island ( ', also known as St. John's Island in English) is the largest of a group of islands in

Foul Bay Foul Bay (, "uncleaned bay"; , ) is a bay on the Egyptian side of the Red Sea, in the Red Sea Governorate. Geography Foul Bay is located slightly north of the Tropic of Cancer. The town which lies at the most inland section of the bay is Berenic ...

Egypt Egypt ( , ), officially the Arab Republic of Egypt, is a country spanning the Northeast Africa, northeast corner of Africa and Western Asia, southwest corner of Asia via the Sinai Peninsula. It is bordered by the Mediterranean Sea to northe ...

. It covers an area of . It is not a

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS), as well as the current and most recent of the twelve periods of the ...

volcanic A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often fo ...

island, but rather is believed to be an upthrust part of

upper mantle The upper mantle of Earth is a very thick layer of rock inside the planet, which begins just beneath the crust (geology), crust (at about under the oceans and about under the continents) and ends at the top of the lower mantle (Earth), lower man ...

material. The nearest island is known as " Rocky Island". The island is slightly north of the

Tropic of Cancer The Tropic of Cancer, also known as the Northern Tropic, is the Earth's northernmost circle of latitude where the Sun can be seen directly overhead. This occurs on the June solstice, when the Northern Hemisphere is tilted toward the Sun ...

, and its highest point is .

History

Before the mid 270s CE
Ptolemaic Ptolemaic is the adjective formed from the name Ptolemy, and may refer to: Pertaining to the Ptolemaic dynasty *Ptolemaic dynasty, the Macedonian Greek dynasty that ruled Egypt founded in 305 BC by Ptolemy I Soter *Ptolemaic Kingdom Pertaining t ...
activity along the African coast of the Red Sea had been limited with few significant results other than the discovery of the 'topaz' deposits on the island of Gazirat Zabarjad southeast of
Ras Banas Ras Banas ( ) is a peninsula in Egypt extending into the Red Sea. The inlet of water sheltered to the south of it is called Foul Bay, at the head of which sits the ancient port of Berenice. It is believed that Mukawwa Island to the south of the ...
. ... 2. Pliny, ''HN'' 37, 108 refers to a large topaz that was brought back to Egypt as a gift for
Ptolemy I Ptolemy I Soter (; , ''Ptolemaîos Sōtḗr'', "Ptolemy the Savior"; 367 BC – January 282 BC) was a Macedonian Greek general, historian, and successor of Alexander the Great who went on to found the Ptolemaic Kingdom centered on Egypt. Pt ...
's queen
Berenice I Berenice I (; c. 340 BC – between 279 and 268 BC) was Queen of Egypt by marriage to Ptolemy I Soter. She became the second queen, after Eurydice, of the Ptolemaic dynasty of Egypt. Life Family Berenice was originally from Eordaea. She was the d ...
.

Geology

The island is considered

geologically Geology (). is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth s ...

unique as it is uplifted mantle, a fragment of the sub-

Red Sea The Red Sea is a sea inlet of the Indian Ocean, lying between Africa and Asia. Its connection to the ocean is in the south, through the Bab-el-Mandeb Strait and the Gulf of Aden. To its north lie the Sinai Peninsula, the Gulf of Aqaba, and th ...

lithosphere A lithosphere () is the rigid, outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust and the lithospheric mantle, the topmost portion of the upper mantle that behaves elastically on time ...

. Rocks on the island are mainly lower crustal

igneous rock Igneous rock ( ), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava. The magma can be derived from partial ...

s. The island became present above sea level after

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

n and

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

tic continental plates converged to cause rocks in the lower crust to be uplifted. The island contains three masses of

peridotite Peridotite ( ) is a dense, coarse-grained igneous rock consisting mostly of the silicate minerals olivine and pyroxene. Peridotite is ultramafic, as the rock contains less than 45% silica. It is high in magnesium (Mg2+), reflecting the high pr ...

, which are rich in the gemstone peridot (olivine). The island is believed to be the first discovered source of peridot, which was called ''topazios'' in ancient times, hence the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

name for the island, ''Topazios''. Layers of

spinel Spinel () is the magnesium/aluminium member of the larger spinel group of minerals. It has the formula in the cubic crystal system. Its name comes from the Latin word , a diminutive form of ''spine,'' in reference to its pointed crystals. Prop ...

lherzolite Lherzolite is a type of ultramafic igneous rock. It is a coarse-grained rock consisting of 40 to 90% olivine along with significant orthopyroxene and lesser amounts of calcic chromium-rich clinopyroxene. Minor minerals include chromium and alumi ...

s with

anhydrous A substance is anhydrous if it contains no water. Many processes in chemistry can be impeded by the presence of water; therefore, it is important that water-free reagents and techniques are used. In practice, however, it is very difficult to achie ...

Al-

diopside Diopside is a monoclinic pyroxene mineral with composition . It forms complete solid solution series with hedenbergite () and augite, and partial solid solutions with orthopyroxene and pigeonite. It forms variably colored, but typically dull ...

pyroxenite Pyroxenite is an ultramafic igneous rock consisting essentially of minerals of the pyroxene group, such as augite, diopside, hypersthene, bronzite or enstatite. Pyroxenites are classified into clinopyroxenites, orthopyroxenites, and the w ...

s and

hydrous In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was understo ...

Cr-diopside pyroxenites can be found on the island. Pliny, XXXV, chap. 22 says that, according to

Juba Juba is the capital and largest city of South Sudan. The city is situated on the White Nile and also serves as the capital of the Central Equatoria, Central Equatoria State. It is the most recently declared national capital and had a populatio ...

, the island "Topazus in the Red Sea", also had mines producing sandarach (

realgar Realgar ( ), also known as arsenic blende, ruby sulphur or ruby of arsenic, is an arsenic sulfide mineral with the chemical formula α-. It is a soft, sectile mineral occurring in monoclinic crystals, or in granular, compact, or powdery form, ...

) and ochre, "but neither of them are imported to us from that place."''The Natural History by Pliny the Elder''. Vol. VI. Translated by John Bostock and H. T. Riley. Henry G. Bohn, York St., Covent Garden, London, pp. 239-240 and n. 34.

Nature

The island is part of the

Elba National Park Gabal Elba ( ', , "Box Mountain"), or Elba Mountain refers to the mountain itself as well as the mountainous area in the Halaib Triangle of Northeast Africa. It is claimed by both Egypt and Sudan, but is under Egyptian control. Geography The hi ...

meaning the island is conserved. However, the island was closed to the public for one year due to damage to corals and the disturbance of birds who breed on the island.

Birds

The island serves as a breeding ground for at least nine known species of birds. The most recent discovery was that of 150 pairs of

sooty falcon The sooty falcon (''Falco concolor'') is a medium-sized falcon breeding from northeastern Africa to the southern Persian Gulf region. The word sooty means to be covered in soot (ash), and is used to describe the color of the Sooty Falcon. Hence, ...

(''Falco concolor'') in October, 1994.

Plantlife

There is very little vegetation on the island due to the lack of soil.

Corals and sealife

The

coral Corals are colonial marine invertebrates within the subphylum Anthozoa of the phylum Cnidaria. They typically form compact Colony (biology), colonies of many identical individual polyp (zoology), polyps. Coral species include the important Coral ...

s surround the island and act as a barrier for the fish and other sea life which live among it. However, the corals recently became damaged due to increased tourist activity and the expansion of the

diving Diving most often refers to: * Diving (sport), the sport of jumping into deep water * Underwater diving, human activity underwater for recreational or occupational purposes Diving or Dive may also refer to: Sports * Dive (American football), ...

industry on the island. The coral is located approximately 25 metres below the surface. Fish that can be found within the nearby waters and corals are: *

Rays Ray or RAY may refer to: Fish * Ray (fish), any cartilaginous fish of the superorder Batoidea * Ray (fish fin anatomy), the bony or horny spine on ray-finned fish Science and mathematics * Half-line (geometry) or ray, half of a line split at an ...

Moray eel Moray eels, or Muraenidae (), are a family (biology), family of eels whose members are found worldwide. There are approximately 200 species in 15 genera which are almost exclusively Marine (ocean), marine, but several species are regu ...

s *

Octopus An octopus (: octopuses or octopodes) is a soft-bodied, eight-limbed mollusc of the order Octopoda (, ). The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids. Like oth ...

* Crocodilefish *

Cuttlefish Cuttlefish, or cuttles, are Marine (ocean), marine Mollusca, molluscs of the order (biology), suborder Sepiina. They belong to the class (biology), class Cephalopoda which also includes squid, octopuses, and nautiluses. Cuttlefish have a unique ...

Tourism

The island is near

coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in group ...

s, which are a popular diving attraction for tourists. The diving industry on the island has increased as well as the tourism industry on the island in general resulting in construction of hotels and diving shelves. The beaches are often quiet and are relatively unspoilt by development. However, most tourists go to this island as a "stop-off" before going to Rocky Island in the south.

References

External links

St. John's Island peridot information and history
at

Mindat.org Mindat.org is a non-commercial interactive online database covering minerals around the world. Originally created by Jolyon Ralph as a private project in 1993, it was launched as a community-editable website in October 2000. it is operated by ...

Bird Life Information
{{Authority control Islands of Egypt Islands of the Red Sea Red Sea Governorate