Peridot
General
Category	Mineral
Chemical formula	(Mg, Fe)2SiO4
Identification
Color	Yellow, to yellow-green, olive-green, to brownish
Crystal system	Orthorhombic
Cleavage	Poor
Fracture	Conchoidal
Mohs Scale hardness	6. A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes A crystal system is a category of Space groups which characterize Symmetry of structures in three dimensions with Translational symmetry in three directions In Crystallography, the orthorhombic Crystal system is one of the seven Lattice Point groups Orthorhombic lattices result from stretching Cleavage, in Mineralogy, is the tendency of crystalline materials to split along definite planes creating smooth surfaces of which there are several named types In the field of Mineralogy, fracture is a term used to describe the shape and texture of the surface formed when a Mineral is broken The Mohs scale of mineral hardness characterizes the scratch resistance of various Minerals through the ability of a harder material to scratch a softer material 5-7
Luster	Vitreous (glassy)
Refractive index	1. Lustre (or luster) is a description of the way light interacts with the surface of a Crystal, rock, or Mineral. The refractive index (or index of Refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves is reduced inside the medium 64-1. 70
Birefringence	+0. Birefringence, or double refraction, is the decomposition of a ray of Light into two rays (the ordinary ray and the extraordinary ray 036
Streak	White
Specific gravity	3. The streak (also called powder color) of a Mineral is the Color of the powder produced when it is dragged across an unweathered surface Specific gravity is defined as the ratio of the Density of a given solid or liquid substance to the density of water at a specific temperature and pressure typically 2-4. 3

Peridot (pronunciation: /ˈpɛrɪˌdɒt/, /ˈpɛrɪˌdoʊ/ (British English), /ˈpɛərɪˌdɑt/, /ˈpɛərɪˌdɑʊ/ (US English)) is the gem quality variety of forsteritic olivine. Forsterite (Mg2SiO4 is the magnesium rich end-member of the Olivine Solid solution series The Mineral olivine (when gem-quality also called Peridot) is a Magnesium Iron silicate with the formula ( Mg The chemical composition of peridot is (Mg, Fe)₂SiO₄, with Mg in greater quantities than Fe. The name of the gemstone is believed to come from either the Arabic word faridat, meaning "gem", or from a Greek word meaning "gold stone". Peridot is one of the few gemstones that comes in only one color. The depth of green depends on how much iron is contained in the crystal structure, and varies from yellow-green to olive to brownish green. Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 Olivine is a very abundant mineral, but gem quality peridot is rather rare. The Mineral olivine (when gem-quality also called Peridot) is a Magnesium Iron silicate with the formula ( Mg Peridot crystals have been collected from some Pallasite meteorites. A pallasite is a type of stony-iron Meteorite. It consists of cm-sized Olivine crystals of Peridot quality in an iron- Nickel matrix A meteorite is a natural object originating in Outer space that survives an impact with the Earth 's surface Peridot olivine is the birthstone for August. Early civilizations such as India and Babylon have attributed gemstones with magical properties Other names In Arabic, the month is called أغسطسص ʾUġusṭuṣ or آب ʾĀb; usage varies from place to place and

Occurrence

Olivine, of which peridot is a type, is a common mineral in mafic and ultramafic rocks, and it is often found in lavas and in peridotite xenoliths of the mantle, which lavas carry to the surface; but gem quality peridot only occurs in a fraction of these settings. Mafic is an adjective describing a Silicate mineral or rock that is rich in magnesium and iron the term was derived by contracting "magnesium" and "ferric" Ultramafic (also referred to as ultrabasic) rocks are igneous and meta -igneous rocks with very low Silica content (less than 45% generally Lava is molten rock expelled by a Volcano during an eruption When first expelled from a volcanic vent it is a Liquid at Temperatures A peridotite is a dense coarse-grained Igneous rock, consisting mostly of the minerals Olivine and Pyroxene. This article concerns the geologic term for other uses see Xenolith (disambiguation A xenolith ( Greek: 'foreign rock' is a rock The mantle is a part of an Astronomical object. The interior of the Earth, similar to the other Terrestrial planets, is Chemically divided Peridot olivine is mined in North Carolina, Arizona, Hawaii, Nevada, and New Mexico, in the US; and in Australia, Brazil, China, Kenya, Mexico, Myanmar (Burma), Norway, Pakistan, South Africa, Sri Lanka, and Tanzania. North Carolina ( is a state located on the Atlantic Seaboard in the southeastern United States The State of Arizona ( is a state located in the southwestern region of the United States. The State of Hawaii ( or həˈwaɪʔiː Hawaiian: Mokuāina o Hawaii) is a state in the United States located on an Archipelago in the Nevada ( is a state located in the western region of the United States of America. New Mexico ( is a state located in the southwestern region of the United States of America. For a topic outline on this subject see List of basic Australia topics. |utc_offset = -2 to -4 |time_zone_DST = BRST |utc_offset_DST = -2 to -5 |cctld China ( Wade-Giles ( Mandarin) Chung¹kuo² is a cultural region, an ancient Civilization, and depending on perspective a National The Republic of Kenya is a country in East Africa. It is bordered by Ethiopia to the north Somalia to the northeast Tanzania to the south The United Mexican States ( or commonly Mexico (ˈmɛksɪkoʊ () is a federal constitutional Republic in North America. Burma, officially the Union of Myanmar ( pjìdàunzṵ mjàmmà nàinŋàndɔ̀ is the largest country by geographical area in mainland Southeast Asia. Norway ( Norwegian: Norge ( Bokmål) or Noreg ( Nynorsk) officially the Kingdom of Norway, is a Constitutional Pakistan () officially the Islamic Republic of Pakistan, is a country located in South Asia, Southwest Asia, Middle East and The Republic of South Africa (also known by other official names) is a country located at the southern tip of the continent of Africa Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka ( Sinhalese:, இலங்கை known as Ceylon before 1972 is an Island Tanzania ˌtænzəˈniːə officially the United Republic of Tanzania (Jamhuri ya Muungano wa Tanzania is a country in East Africa bordered by Kenya High quality peridot olivine is mined in the eastern lava fields of Saudi Arabia. The Kingdom of Saudi Arabia, KSA ( المملكة العربية السعودية, al-Mamlaka al-ʻArabiyya as-Suʻūdiyya) or Suudi The largest cut peridot olivine is a 310 carat (62 g) specimen in the Smithsonian Museum in Washington, D.C.. The carat is a unit of Mass used for measuring gems and Pearls Currently a carat is defined as exactly 200  mg (0 The Smithsonian Institution (smɪθsoʊnɪən is an educational and research institute and associated Museum complex administered and funded by the Government of Washington DC ( formally the District of Columbia and commonly referred to as Washington, the District, or simply D

Peridot olivine with minor pyroxene, on vesicular basalt. The pyroxenes are a group of important rock-forming Silicate minerals found in many Igneous and metamorphic rocks. Basalt (bəˈsɔːlt ˈbeisɔːlt ˈbæsɔːlt is a common Extrusive Volcanic rock. (FOV = 60mm)

Peridot from the San Carlos Apache reservation in Arizona.

External links

• Mineral Galleries - Peridot
• Gemstone.org Peridot
• USGS peridot data
• Emporia Edu
• Florida State U. - Peridot