Zircon

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Zircon

Zircon is a mineral

Mineral

A mineral is a naturally occurring solid formed through Geology processes that has a characteristic chemical composition, a highly ordered atomic structure, and specific physical properties....
belonging to the group of nesosilicates

Silicate minerals

The silicate minerals make up the largest and most important class of rock-forming minerals, comprising approximately 90 percent of the crust of the Earth....
. Its chemical name is zirconium silicate and its corresponding chemical formula is Zr

Zirconium

Zirconium is a chemical element with the symbol Zr and atomic number 40. It is a lustrous, gray-white, strong transition metal that resembles titanium....
Si

Silicon

Silicon is the most common metalloid. It is a chemical element, which has the symbol Si and atomic number 14. The atomic mass is 28.0855....
O

Oxygen

Oxygen no O2 produced; 2) O2 produced, but absorbed in oceans & seabed rock; 3) O2 starts to gas out of the oceans, but is absorbed by land surfaces and formation of ozone layer; 4-5) O2 sinks filled and the gas accumulates]]...
₄. Hafnium

Hafnium

Hafnium is a chemical element with the element symbol Hf and atomic number 72. A lustre , silvery gray, tetravalence, transition metal, hafnium chemically resembles zirconium and is found in zirconium minerals....
is almost always present in quantities ranging from 1 to 4%. The crystal structure of zircon is tetragonal crystal system

Crystal system

A crystal system is a category of space groups, which characterize symmetry of structures in three dimensions with translational symmetry in three directions, having a discrete class of Point groups in three dimensions....
. The natural color of zircon varies between colorless, yellow-golden, red, brown, and green. Colorless specimens that show gem quality are a popular substitute for diamond

Diamond

In mineralogy, diamond is the Allotropes of carbon where the carbon atoms are arranged in an isometric-hexoctahedral crystal lattice. After graphite, diamond is the second most stable form of carbon....
; these specimens are also known as "Matura diamond".

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Encyclopedia

Zircon is a mineral

Mineral

Silicate minerals

Zirconium

Zirconium is a chemical element with the symbol Zr and atomic number 40. It is a lustrous, gray-white, strong transition metal that resembles titanium....
Si

Silicon

Silicon is the most common metalloid. It is a chemical element, which has the symbol Si and atomic number 14. The atomic mass is 28.0855....
O

Oxygen

Hafnium

Crystal system

Diamond

Cubic zirconia

Cubic zirconia , is the cubic crystalline form of zirconium oxide . The synthesized material is hard, optically flawless and usually colorless, but may be made in a variety of different colors....
, a synthetic substance with a completely different chemical composition.

The name either derives from the Arabic

Arabic language

Arabic is a Central Semitic language, thus related to and classified alongside other Semitic languages languages such as Hebrew language and Aramaic language....
word zarqun, meaning vermilion

Vermilion

Vermilion, sometimes spelled vermillion, when found naturally occurring, is an opaque Orange ish red pigment, used since antiquity, originally derived from the powdered mineral cinnabar....
, or from the Persian

Persian language

Jargoon

A Jargoon or jargon is name applied by Gemology to those zircons which are fine enough to be cut as gemstones, but are not of the red color which characterizes the hyacinth or jacinth....
", a term applied to light-colored zircons. Yellow zircon is called hyacinth, from the flower hyacinthus

Hyacinthus

Hyacinthus can refer to:*Hyacinth *Hyacinth Excess long comment to prevent listing on...
, whose name is of Ancient Greek origin; in the Middle Ages all yellow stones of East Indian origin were called hyacinth, but today this term is restricted to the yellow zircons.

Zircon is regarded as the traditional birthstone for December.

Properties

Zircon is a remarkable mineral, if only for its almost ubiquitous presence in the crust

Crust (geology)

In geology, a crust is the outermost solid shell of a planet or moon, which is chemically distinct from the underlying mantle . Crusts of Earth , our Moon, Mercury , Venus, and Mars have been generated largely by igneous processes, and these crusts are richer in incompatible elements than their respective mantle s....
of Earth. It occurs in igneous rock

Igneous rock

Igneous rock is one of the three main Rock types . Igneous rock is formed by magma being cooled and becoming solid . They may form with or without crystallization, either below the surface as Intrusion rocks or on the surface as extrusive rocks....
s (as primary crystallization products), in metamorphic rock

Metamorphic rock

Metamorphic rock is the result of the transformation of an existing rock type, the protolith, in a process called metamorphism, which means "change in form"....
s and in sedimentary rock

Sedimentary rock

Sedimentary rock is one of the three main Rock types . Sedimentary rock is formed by deposition and consolidation of mineral and organic material and from precipitation of minerals from solution....
s (as detrital grains). Large zircon crystals are seldom abundant. Their average size, e.g. in granite rocks, is about 100–300 µm, but they can also grow to sizes of several centimeters, especially in pegmatite

Pegmatite

Uranium

Uranium is a silvery-gray metallic chemical element in the actinide series of the periodic table that has the chemical symbol U and atomic number 92....
and thorium

Thorium

Thorium is a chemical element with the symbol Th and atomic number 90. As a naturally occurring, slightly radioactive metal, it has been considered as an alternative nuclear fuel to uranium....
content, some zircons may undergo metamictization

Metamictization

Metamictization is a natural process resulting in the gradual and ultimately complete destruction of a mineral's crystal lattice, leaving the mineral amorphous....
. The processes related to internal radiation damage partially disrupts the crystal structure and partly explains the highly variable properties of zircon. As zircon becomes more and more modified by internal radiation damage, the density decreases, the crystal structure is compromised, and the color changes.

Zircon is a common accessory mineral that occurs worldwide. Noted occurrences include: Australia

Australia

Australia, officially the Commonwealth of Australia, is a country in the southern hemisphere comprising the Australia of the world's smallest continent, the major island of Tasmania, and numerous list of islands of Australia in the Indian Ocean and Pacific Oceans....
; the Ural Mountains

Ural Mountains

The Ural Mountains are a mountain range that runs roughly north and south through western Russia. They are usually considered as the natural boundary between Europe and Asia....
; Trentino, Monte Somma, and Vesuvius, Italy

Italy

Italy , officially the Italian Republic , is a country located on the Italian Peninsula in Southern Europe and on the two largest islands in the Mediterranean Sea, Sicily and Sardinia....
; Arendal, Norway

Norway

Norway , officially the Kingdom of Norway, is a constitutional monarchy in Northern Europe that occupies the western portion of the Scandinavian Peninsula....
; Sri Lanka

Sri Lanka

Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka is an island country in South Asia, located about off the southern coast of India....
; India

India

India, officially the Republic of India , is a country in South Asia. It is the List of countries and outlying territories by total area country by geographical area, the List of countries by population country, and the most populous liberal democracy in the world....
; Thailand

Thailand

The Kingdom of Thailand is an independent country that lies in the heart of Southeast Asia. It is bordered to the north by Laos and Myanmar, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the west by the Andaman Sea and Myanmar....
; Ratanakiri

Ratanakiri

Ratanakiri is a Administrative divisions of Cambodia in northeastern Cambodia that borders Laos to the north, Vietnam to the east, Mondulkiri Province to the south, and Stung Treng Province to the west....
, Cambodia

Cambodia

The Kingdom of Cambodia is a country in South East Asia with a population of over 13 million people. The kingdom's capital and largest city is Phnom Penh....
; the Kimberley mines, Republic of South Africa; Madagascar

Madagascar

Madagascar, or Republic of Madagascar , is an island nation in the Indian Ocean off the southeastern coast of Africa. The main island, also called Madagascar, is the List of islands by area, and is home to 5% of the world's plant and animal species, of which more than 80% are Endemism to Madagascar....
; Renfrew County, Ontario

Ontario

Ontario is a Provinces and territories of Canada located in the Central Canada part of Canada, the largest by population and second largest, after Quebec, in total area....
, and Grenville, Quebec

Grenville, Quebec

Grenville is a village and municipality in the Argenteuil Regional County Municipality, Quebec, Canada. It is located opposite Hawkesbury, Ontario, on the Ottawa River....
, Canada

Canada

Canada is a country occupying most of northern North America, extending from the Atlantic Ocean in the east to the Pacific Ocean in the west and northward into the Arctic Ocean....
; and Litchfield, Maine

Litchfield, Maine

Litchfield is a town in Kennebec County, Maine, Maine, United States. The population was 3,110 at the 2000 United States Census.Geography...
; Chesterfield, Massachusetts

Chesterfield, Massachusetts

Chesterfield is a rural recreational hill New England town in Hampshire County, Massachusetts, Massachusetts, United States, 28 miles southeast of Pittsfield, Massachusetts and 108 miles west of Boston....
; Essex, Orange, and St. Lawrence counties, New York

New York

The State of New York is a U.S. state in the Mid-Atlantic States and Northeastern United States regions of the United States and is the nation's List of U.S....
; Henderson County, North Carolina

Henderson County, North Carolina

Henderson County is a county located in the U.S. state of North Carolina. It is part of the Asheville, North Carolina, Asheville metropolitan area....
; the Pikes Peak

Pikes Peak

Pikes Peak is a mountain in the Front Range of the Rocky Mountains, west of Colorado Springs, Colorado, in El Paso County, Colorado. It is named for Zebulon Pike, an explorer who led an expedition to the southern Colorado area in 1806....
district of Colorado

Colorado

The State of Colorado is a U.S. state located in the Mountain States of the United States of America. Colorado may also be considered to be a part of the Western United States and Southwestern United States regions of the United States....
; and Llano County, Texas

Llano County, Texas

Llano County is a county located in the U.S. state of Texas. In 2000, its population was 17,044. Its county seat is Llano, Texas, and the county is named for the Llano River....
in the United States

United States

The United States of America is a Federal government constitutional republic comprising U.S. state and a federal district. The country is situated mostly in central North America, where its Contiguous United States and Washington, D.C., the Capital districts and territories, lie between the Pacific Ocean and Atlantic Oceans, Borders of the U...
. Australia leads the world in zircon mining, producing 37% of the world total and accounting for 40% of world EDR (economic demonstrated resources) for the mineral. Thorite

Thorite

Thorite, SiO4, is a rare Silicate minerals of thorium that crystallizes in the tetragonal system and is isomorphous with zircon. It is the most common mineral of thorium and is nearly always strongly Radioactivity....
(ThSiO₄) is an isostructural related mineral.

Zircon occurs in many different colors including red, pink, brown, yellow, hazel, black, or colorless. The color of zircons can be changed by heat treatment. Depending on the amount of heat applied, colorless, blue, and golden-yellow zircons can be made. In geological settings, the development of pink, red, and purple zircon occurs after 100's of millions of years provided the crystal has sufficient trace elements to produce color centers. Color in this red or pink series is annealed in geological conditions above about 350°C.

Uses

Zircons are commercially mined for the metal zirconium, and are used for abrasive and insulating purposes.
It is the source of zirconium oxide(ZrO₂), one of the most refractory
Refractory

A refractory material is one that retains its strength at high temperatures. ASTM International C71 defines refractories as "non-metallic materials having those chemical and physical properties that made them applicable for structures, or as components of systems, that are exposed to environments above 1000 ?F "....
materials known.
Crucibles of ZrO₂ are used to fuse platinum
Platinum

Platinum is a chemical element with the chemical symbol Pt and an atomic number of 78. Its name is derived from the Spanish term platina del Pinto, which is literally translated into "little silver of the Pinto River." It is in Group 10 of the periodic table of elements....
at temperatures in excess of 1755 ^oC.
Zirconium metal is used in nuclear reactors due to its neutron
Neutron

The neutron is a subatomic particle with no net electric charge and a mass slightly larger than that of a proton.Neutrons are usually found in atomic nucleus....
absorption properties.
Large specimens are appreciated as gemstone
Gemstone

A gemstone or gem, also called a precious or semi-precious stone, is a piece of attractive mineral, which — when cut and polished — is used to make jewellery or other adornments....
s, owing to their high refractive index
Refractive index

The refractive index of a medium is a measure for how much the speed of light is reduced inside the medium. For example, typical soda-lime glass has a refractive index of 1.5, which means that in glass, light travels at times the speed of light in a vacuum....
. (Zircon has a refractive index of approximately 1.95; diamond
Diamond

In mineralogy, diamond is the Allotropes of carbon where the carbon atoms are arranged in an isometric-hexoctahedral crystal lattice. After graphite, diamond is the second most stable form of carbon....
's is approximately 2.4.)
Zircon is one of the key minerals used by geologists for geochronology
Geochronology

In the natural sciences under the umbrella of natural history, Geochronology is the science of determining the absolute age of rock , fossils, and sediments, within a certain degree of uncertainty inherent within the method used....
.

Occurrence

Zircon is a common accessory to trace mineral constituent of most granite

Granite

Granite is a common and widely occurring type of Intrusion , felsic, igneous rock rock . Granite has a medium to coarse texture, occasionally with some individual crystals larger than the groundmass forming a rock known as Porphyry ....
and felsic igneous rocks. Due to its hardness, durability and chemical inertness, zircon persists in sedimentary deposits and is a common constituent of most sands. Zircon is rare within mafic rocks and very rare within ultramafic rocks aside from a group of ultrapotassic intrusive rocks such as kimberlite

Kimberlite

Kimberlite is a type of potassic volcanic rock best known for sometimes containing diamonds. It is named after the town of Kimberley, Northern Cape in South Africa, where the discovery of an diamond in 1871 spawned a diamond rush, eventually creating the Big Hole....
s, carbonatites, and lamprophyre, where zircon can occasionally be found as a trace mineral owing to the unusual magma genesis of these rocks.

Zircon forms economic concentrations within heavy mineral sands ore deposits

Heavy mineral sands ore deposits

Heavy mineral sands are a class of ore deposit which is an important source of zirconium, titanium, thorium, tungsten, rare earth elements, the industrial minerals diamond, sapphire, garnet, and occasionally precious metals or gemstones....
, within certain pegmatite

Pegmatite

Pegmatite is a very coarse-grained igneous rock that has a grain size of 20 mm or more; such rocks are referred to as pegmatitic.Most pegmatites are composed of quartz, feldspar and mica; in essence a "granite"....
s, and within some rare alkaline volcanic rocks, for example the Toongi Trachyte, Dubbo, New South Wales Australia in association with the zirconium-hafnium minerals eudialyte

Eudialyte

File:Eudialyte in Syenite.jpgEudialyte, whose name derives from the Greek eu and dialysis, meaning "well decomposable", is a somewhat rare, red silicate mineral, which forms in alkaline igneous rocks, such as nepheline syenites....
and armstrongite.

Zircons and radiometric dating

Zircon has played an important role during the evolution of radiometric dating

Radiometric dating

Radiometric dating is a technique used to date materials, usually based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates....
. Zircons contain trace amounts of uranium

Uranium

Uranium is a silvery-gray metallic chemical element in the actinide series of the periodic table that has the chemical symbol U and atomic number 92....
and thorium

Thorium

Erosion

For morphological image processing operations, see Erosion 'For use of in dermatopathology, see Erosion Erosion is the removal of solids in the natural environment....
, transport, even high-grade metamorphism

Metamorphism

Metamorphism is the solid-state Crystallization of pre-existing Rock due to changes in physical and chemical conditions, primarily heat, pressure, and the introduction of chemically active fluids....
, they contain a rich and varied record of geological processes. Currently, zircons are typically dated by U/Pb, fission-track dating, and U+Th/He dating techniques.

The oldest minerals

Oldest rock

The oldest rock or Rock on Earth, as an aggregate of minerals that have not been subsequently melted or disaggregated by erosion, are from the Archean Eon ....
dated so far by the U/Pb technique are zircons from Jack Hills

Jack Hills

File:Jack hills etm 1999208.jpgThe Jack Hills are a range of hills in Mid West Western Australia. They are best known as the source of the oldest material of terrestrial origin found to date: zircons that formed nearly 4? billion years ago....
in the Narryer Gneiss Terrane

Narryer Gneiss Terrane

The Narryer Gneiss Terrane is a geological complex in Western Australia that is composed of a tectonically interleaved and polydeformed mixture of granite, mafic intrusions and metasedimentary rocks in excess of 3.3 Ga, with the majority of the Narryer Gneiss Terrane in excess of 3.6 Ga....
, Yilgarn Craton

Yilgarn craton

The Yilgarn Craton is a large craton which constitutes the bulk of the Western Australian land mass. It is bounded by a mixture of sedimentary basins and Proterozoic fold and thrust belts....
, Western Australia

Western Australia

Western Australia is a States and territories of Australia occupying the entire western third of the Australia . The nation's largest state and the second largest subnational entity in the world, it has 2.1 million inhabitants , 85% of whom live in the south-west corner of the state....
, with an age of 4.404 billion years, interpreted to be the age of crystallization. These zircons might be the oldest minerals on earth. In addition, the oxygen

Oxygen

Isotope

Isotopes are any of the different types of atoms of the same chemical element, each having a different atomic mass . Isotopes of an element have atomic nucleus with the same number of protons but different numbers of neutron....
composition has been interpreted to indicate that more than 4.4 billion years ago there was already water on the surface of the Earth. This interpretation has been published in scientific journals but is the subject of debate.

Zircon

Properties

Uses

Occurrence

Zircons and radiometric dating

Gallery

See also

Further reading