Lizardite is a mineral from the serpentine subgroup with formula , and the most common type of mineral in the subgroup. It is also a member of the kaolinite-serpentine group. Lizardite may form a solid-solution series with the nickel-bearing népouite (pure end-member: ). Intermediate compositions are possible, with varying proportions of

magnesium Magnesium is a chemical element; it has Symbol (chemistry), symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 ...

and

nickel Nickel is a chemical element; it has symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive, but large pieces are slo ...

. However, the lizardite end-member is much more common than pure népouite, a relatively rare mineral most often formed by the alteration of

ultramafic Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are usua ...

rocks. Extremely fine-grained, scaly lizardite (also called orthoantigorite) comprises much of the serpentine present in "serpentine

marble Marble is a metamorphic rock consisting of carbonate minerals (most commonly calcite (CaCO3) or Dolomite (mineral), dolomite (CaMg(CO3)2) that have recrystallized under the influence of heat and pressure. It has a crystalline texture, and is ty ...

s". It is

triclinic class=skin-invert-image, 180px, Triclinic (a ≠ b ≠ c ≠ a and α, β, γ, 90° pairwise different) In crystallography, the triclinic (or anorthic) crystal system is one of the seven crystal systems. A crystal system is described by three b ...

, has one direction of perfect cleavage, and may be white, yellow or green. Lizardite can be translucent or opaque, and have a soapy feel. It may be

pseudomorph In mineralogy, a pseudomorph is a mineral or mineral compound that appears in an atypical form (crystal system), resulting from a substitution process in which the appearance and dimensions remain constant, but the original mineral is replaced b ...

ous after enstatite,

olivine The mineral olivine () is a magnesium iron Silicate minerals, silicate with the chemical formula . It is a type of Nesosilicates, nesosilicate or orthosilicate. The primary component of the Earth's upper mantle (Earth), upper mantle, it is a com ...

pyroxene The pyroxenes (commonly abbreviated Px) are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents ions of calcium (Ca), sodium (Na), iron ( ...

, in which case the name bastite is sometimes applied. Bastite may have a silky lustre.

Name

Lizardite was named by Eric James William Whittaker and Jack Zussman in 1955 after the place it was first reported, the

Lizard Peninsula The Lizard () is a peninsula in southern Cornwall, England, United Kingdom. The Extreme points of the United Kingdom, southernmost point of the Great Britain, British mainland is near Lizard Point, Cornwall, Lizard Point at SW 701115; The ...

, (from the ) in southern

Cornwall Cornwall (; or ) is a Ceremonial counties of England, ceremonial county in South West England. It is also one of the Celtic nations and the homeland of the Cornish people. The county is bordered by the Atlantic Ocean to the north and west, ...

, England,

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

. Scyelite is a synonym of lizardite.

Characteristics

Chemistry

Antigorite and lizardite commonly coexist metastably; lizardite may also be able to turn into antigorite at over 350 degrees. Lizardite contains H₂O in excess of the nominal formula, as does

chrysotile Chrysotile or white asbestos is the most commonly encountered form of asbestos, accounting for approximately 95% of the asbestos in the United StatesOccupational Safety and Health Administration, U.S. Department of Labor (2007)29 C.F.R.&nb ...

. It has a high amount of Fe₂O₃ and a low amount of FeO. One study found that lizardite has a high amount of SiO₂ and a low amount of Al₂O₃.

Formation

Lizardite is commonly a result from the hydrothermal metamorphism or

retrograde metamorphism Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place at temperatures in excess of , and often also at elevated pressure or in the presence of c ...

mafic A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks include ...

minerals such as

amphibole Amphibole ( ) is a group of inosilicate minerals, forming prism or needlelike crystals, composed of double chain tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures. Its IMA symbol is ...

, in ultrabasic rocks.

Occurrence

Geological occurrence

Lizardite is commonly found in

ophiolite An ophiolite is a section of Earth's oceanic crust and the underlying upper mantle (Earth), upper mantle that has been uplifted and exposed, and often emplaced onto continental crustal rocks. The Greek word ὄφις, ''ophis'' (''snake'') is ...

and is often intergrown with

brucite Brucite is the mineral form of magnesium hydroxide, with the chemical formula Magnesium, Mg(hydroxyl, OH)2. It is a common alteration product of periclase in marble; a low-temperature hydrothermal Vein (geology), vein mineral in metamorphosed li ...

. It is also found with

magnetite Magnetite is a mineral and one of the main iron ores, with the chemical formula . It is one of the iron oxide, oxides of iron, and is ferrimagnetism, ferrimagnetic; it is attracted to a magnet and can be magnetization, magnetized to become a ...

and the other serpentine minerals.

Locations found

Canada

As of 1989, only a single specimen of lizardite had been found in Mont-Saint-Hilaire, Quebec where it may occur in altered

pegmatite A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than and sometimes greater than . Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic c ...

United States

Lizardite can be found in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

. In

Pennsylvania Pennsylvania, officially the Commonwealth of Pennsylvania, is a U.S. state, state spanning the Mid-Atlantic (United States), Mid-Atlantic, Northeastern United States, Northeastern, Appalachian, and Great Lakes region, Great Lakes regions o ...

It was discovered in the 1960s. With it being the most abundant mineral in Nottingham County Park. In

Minnesota Minnesota ( ) is a U.S. state, state in the Upper Midwestern region of the United States. It is bordered by the Canadian provinces of Manitoba and Ontario to the north and east and by the U.S. states of Wisconsin to the east, Iowa to the so ...

it can be found on the north shore of

Lake Superior Lake Superior is the largest freshwater lake in the world by surface areaThe Caspian Sea is the largest lake, but is saline, not freshwater. Lake Michigan–Huron has a larger combined surface area than Superior, but is normally considered tw ...

. In

Montana Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...

, the

Stillwater igneous complex The Stillwater igneous complex is a large layered mafic intrusion (LMI) located in southern Montana in Stillwater, Sweet Grass and Park Counties. The complex is exposed across 30 miles (48 km) of the north flank of the Beartooth Mount ...

is a prominent location for the mineral.

United Kingdom

Lizardite has a type locality at Lizard Peninsula, Cornwall, in the United Kingdom. It is found in green, red purple, brown and black form and used as both a semi-precious gemstone or for ornamental uses.

Scotland Scotland is a Countries of the United Kingdom, country that is part of the United Kingdom. It contains nearly one-third of the United Kingdom's land area, consisting of the northern part of the island of Great Britain and more than 790 adjac ...

is a notable source of lizardite. Lizardite has been reported in

Wales Wales ( ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by the Irish Sea to the north and west, England to the England–Wales border, east, the Bristol Channel to the south, and the Celtic ...

. At

Holy Island, Anglesey Holy Island (, 'the island of (Saint) Cybi') is an island on the western side of the larger Isle of Anglesey, Wales, from which it is separated by the Cymyran Strait. It is called "Holy" because of the high concentration of standing stones, bur ...

lizardite has been found to be associated with antigorite.

South Africa

In the Frank Smith mine located in

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

, lizardite was the dominant serpentine mineral. Orange lizardite has been found at the Wessels mine.

Other

It can also be found in

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

Italy Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...

, and

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

References

{{Phyllosilicates Serpentine group