Omar Rodríguez‑López

16 Oct Omar Rodríguez‑López

Feldspar minerals have very comparable structures, chemical compositions, and bodily properties. Feldspat was introduced in the 18th century as a more specific term, referring perhaps to its common occurrence in rocks found in fields (Urban Brückmann, 1783). Substances for which classification and labelling data have been notified to ECHA by manufacturers or importers. Those that have been recorded to occur as substitutions within the feldspar structures include lithium (Li), rubidium (Rb), cesium (Cs), magnesium (Mg), strontium (Sr), barium (Ba), yttrium (Y), ferrous iron (Fe 2+), thallium (Tl), lead (Pb), lanthanum (La) and other rare earth elements, and ammonium (NH 4) in the A position; and titanium (Ti), ferric (Fe 3+) and ferrous (Fe 2+) iron, boron (B), gallium … conchoidal, uneven . Feldspar is the name given to a group of minerals distinguished by the presence of alumina and silica (SiO 2) in their chemistry. Volumes 1 and 2 of Feldspar Minerals were published in 1974, but Volume 3 was not completed because I was forced to devote 3 years to the resolution of unforeseen problems in the construction of an ion probe. Therefore, the key difference between quartz and feldspar is that the major chemical element present in quartz is silicon whereas in feldspar it is aluminum. Several other elements also have been recorded as traces in feldspar analyses; it seems very likely, however, that some of these elements may reside in impurities—i.e., within unrecognized microscopic or submicroscopic inclusions of other minerals. If at least one company has indicated that the substance classification is affected by impurities or additives, this will be indicated by an informative sentence. “Feldspar” is the name of a large group of rock-forming silicate minerals that make up over 50% of Earth’s crust. In any case, perthite is the name properly applied to intimate mixtures in which the potassium feldspar component predominates over the plagioclase constituent, whereas antiperthite is the name given to intimate mixtures in which the plagioclase constituent is predominant. Spat had long been used as the word for "a rock easily cleaved into flakes". The term silicate stands for a combination of silicon and oxygen. (This designation is used to specify the fractions of the constituents. Black Friday Sale! Please be aware there may be intermittent unavailability while work in ongoing. The molecular structure is based on structures generated from information available in ECHA’s databases. Fracture. If a substance is classified under multiple CLH entries, a link to the C&L Inventory is provided to allow users to view CLH information associated with the substance and no text is automatically generated for the InfoCard. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. The names of members of the series designate relative proportions of the end-members. If the substance is covered by more than one CLH entry (e.g. Here you can find all of the regulations and regulatory lists in which this substance appears, according to the data available to ECHA. The resulting zoning may be gradational or well-defined or may assume some combination of these characteristics. triclinic, monoclinic. The POPs Regulation bans or severely restricts the production and use of persistent organic pollutants in the European Union. the electronic edition of the Official Journal of the European Union. The alkali (Or-Ab) series exhibits complete solid solution at high temperatures but only incomplete solid solution at low temperatures; substitution of potassium for sodium is involved. Those that have been recorded to occur as substitutions within the feldspar structures include lithium (Li), rubidium (Rb), cesium (Cs), magnesium (Mg), strontium (Sr), barium (Ba), yttrium (Y), ferrous iron (Fe2+), thallium (Tl), lead (Pb), lanthanum (La) and other rare earth elements, and ammonium (NH4) in the A position; and titanium (Ti), ferric (Fe3+) and ferrous (Fe2+) iron, boron (B), gallium (Ga), germanium (Ge), and phosphorus (P) in the T position. More information about CAS and the CAS registry can be found here. Some substance identifiers may have been claimed confidential, or may not have been provided, and therefore not be displayed. The CLP Regulation makes sure that the hazards presented by chemicals are clearly communicated to workers and consumers in the European Union. Please upgrade your Internet Explorer to a newer version. As is apparent from the preceding statements, solid solution plays an important role in the rock-making feldspars. Perthites are common, whereas antiperthites are relatively rare. The REACH registered substance data and the C&L Inventory portal will be upgraded from the 9th November. For example, Or80 indicates that the mineral is composed of 80 percent KAlSi3O8 and 20 [i.e., 100 − 80] percent NaAlSi3O8.) ECHA maintains the C&L Inventory, but does not review or verify the accuracy of the information. The date of the last update corresponds to the publication date of the InfoCard and not necessarily to the date in which the update occurred in the source data. KAlSi3O8 – NaAlSi3O8 – CaAl2Si2O8. As another important difference between quartz and feldspar we can say that the repeating unit of quartz is SiO 4 while the repeating unit of feldspar is KAlSi 3 O 8 – NaAlSi 3 O 8 – CaAl 2 Si 2 O 8 . Substances listed in the EINECS, ELINCS, or NLP inventories. It covers their hazardous properties, classification and labelling, and information on how to use them safely. For example, zoned crystals may form with differing An contents arranged one on top of another so that their margins are relatively sodium-rich as compared to their earlier-formed, more calcium-rich cores. It is extracted from large granite formations. The CLP Regulation ensures that the hazards presented by chemicals are clearly communicated to workers and consumers in the European Union through classification and labelling of chemicals. Likewise the per substance indication of harmonised C&L, Seveso directive, or notified C&L regulatory context will be made available as soon as possible. Feldspar is the most abundant mineral group in the Earth’s crust. Feldspar is the name of a large organization of rock-forming silicate minerals that make up over 50% of Earth’s crust. This information is only displayed if the substance is well-defined, its identity is not claimed confidential and there is sufficient information available in ECHA’s databases for ECHA’s algorithms to generate a molecular structure. Harmonisation is based on the substance’s physical, toxicological and eco-toxicological hazard assessment. This is unique source of information on the chemicals manufactured and imported in Europe. Hazard statements were adapted to improve readability and may not correspond textually to the hazard statements codes description in the European Union Specific Hazard Statements (EUH) or the. Many perthites are formed when high-temperature potassium-sodium feldspars of appropriate compositions are cooled in such a manner that the original solid-solution phase exsolves (i.e., unmixes, so that a homogeneous mineral separates into two or more different minerals) to form intermixtures—sometimes termed intergrowths—of two phases. Upon cooling, the first crystals that form from a melt with the composition X (= An50) will have the composition Y (approximately An83). Harmonised classification and labelling is a legally binding classification and labelling for a substance, agreed at European Community level. One explanation for zoning in plagioclases formed from magmas can be implied from information known about the Ab-An system. Although plagioclase grains in some rocks are essentially homogeneous, those in many rocks are zoned—i.e., different parts of individual grains have different Ab and An contents. Substances may have impurities and additives that lead to different classifications. Experimentally, K-feldspar and other feldspar minerals are known to be good ice-nucleating agents, which play a significant role in atmospheric science. All the rock-forming feldspars are aluminosilicate minerals with the general formula AT4O8 in which A = potassium, sodium, or calcium (Ca); and T = silicon (Si) and aluminum (Al), with a Si:Al ratio ranging from 3:1 to 1:1. InfoCards are updated when new information is available. REACH regulation aims to improve the protection of human health and the environment from the risks that can be posed by chemicals. Feldspar The name feldspar derives from the German Feldspat, a compound of the words Feld (field) and Spat (flake). Please note that it may take a week or two to have everything fully in place, and please be aware in the meantime that the Registration status may be incorrect and the CLP regulatory context may be incompletely shown. ECHA organises consultations to get feedback from all interested parties and to gather the widest possible range of scientific information for the regulatory processes. The ‘Hazard classification and labelling’ section shows the hazards of a substance based on the standardised system of statements and pictograms established under the CLP (Classification Labelling and Packaging) Regulation. If available, additional information on classification and labelling (C&L) is derived from REACH registration dossiers submitted by industry. This website uses cookies to ensure you get the best experience on our websites ( and earlier )!, chemical compositions lie between or and Ab not maintained during cooling, the first two are displayed a! Designate relative proportions of the European Union Specific hazard statements used to specify the fractions the... Lead to different classifications REACH registered substance data and the perthites are alkali,. The non-confidential data of a large organization of rock-forming silicate minerals that make up over 50 % of ’! Labelling for a combination of silicon and oxygen numerical identifier for substances in EC! 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