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Brettellier (talk | contribs) m Added citation supporting the claim of diatomaceous earth consisting of fossilized remains of diatoms |
Brettellier (talk | contribs) m Added citation to support claim that composition of diatomaceous earth differs and that it combines with clays and/or minerals. |
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'''Diatomaceous earth''' ({{IPAc-en|ˌ|d|aɪ|.|ə|t|ə|ˈ|m|eɪ|ʃ|ə|s}} {{respell|DY|ə|tə|MAY|shəs}}), '''diatomite''' ({{IPAc-en|d|aɪ|ˈ|æ|t|ə|m|aɪ|t}} {{respell|dy|AT|ə|myte}}), '''celite''' or '''kieselgur'''/'''kieselguhr''' is a naturally occurring, soft, [[siliceous rock|siliceous]] [[sedimentary rock]] that can be crumbled into a fine [[shades of white|white to off-white]] powder. It has a [[particle size]] ranging from more than 3 [[millimeter|mm]] to less than 1 [[micrometre|μm]], but typically 10 to 200 μm<ref>{{Cite journal |last=Dobrosielska |first=Marta |last2=Dobrucka |first2=Renata |last3=Brząkalski |first3=Dariusz |last4=Frydrych |first4=Miłosz |last5=Kozera |first5=Paulina |last6=Wieczorek |first6=Monika |last7=Jałbrzykowski |first7=Marek |last8=Kurzydłowski |first8=Krzysztof J. |last9=Przekop |first9=Robert E. |date=2022-05-18 |title=Influence of Diatomaceous Earth Particle Size on Mechanical Properties of PLA/Diatomaceous Earth Composites |url=https://www.mdpi.com/1996-1944/15/10/3607 |journal=Materials |language=en |volume=15 |issue=10 |pages=3607 |doi=10.3390/ma15103607 |issn=1996-1944 |pmc=PMC9145730 |pmid=35629631}}</ref>. Depending on the [[granularity]], this powder can have an [[abrasive]] feel, similar to [[pumice]] powder, and has a low [[density]] as a result of its high [[porosity]]. The typical chemical composition of oven-dried diatomaceous earth is 80–90% [[silica]], with 2–4% [[aluminum oxide|alumina]] (attributed mostly to [[clay mineral]]s), and 0.5–2% [[iron oxide]].<ref name="USGS">{{cite book |last=Antonides |first=Lloyd E. |title=Diatomite |year=1997 |publisher=[[United States Geological Survey|USGS]] |url=https://minerals.usgs.gov/minerals/pubs/commodity/diatomite/250497.pdf |access-date=December 12, 2010}}</ref>
Diatomaceous earth consists of the [[fossil]]ized remains of [[diatom]]s, a type of hard-shelled [[microalgae]].<ref name=":0">{{Cite journal |last=Rojht |first=Helena |last2=Horvat |first2=Aleksander |last3=Athanassiou |first3=Christos G. |last4=Vayias |first4=Bill J. |last5=Tomanović |first5=Željko |last6=Trdan |first6=Stanislav |date=2010-12 |title=Impact of geochemical composition of diatomaceous earth on its insecticidal activity against adults of Sitophilus oryzae (L.) (Coleoptera: Curculionidae) |url=http://link.springer.com/10.1007/s10340-010-0313-6 |journal=Journal of Pest Science |language=en |volume=83 |issue=4 |pages=429–436 |doi=10.1007/s10340-010-0313-6 |issn=1612-4758}}</ref> It is used as a [[filtration]] aid, mild abrasive in products including metal polishes and [[toothpaste]], mechanical [[insecticide]], [[absorption (chemistry)|absorbent]] for liquids, matting agent for coatings, reinforcing filler in plastics and rubber, anti-block in plastic films, porous support for chemical catalysts, [[Litter box|cat litter]], activator in [[coagulation]] studies, a stabilizing component of [[dynamite]], a [[thermal insulation|thermal insulator]], and a soil for potted plants and trees as in the art of [[bonsai]].<ref>{{cite journal |last1=Reka |first1=Arianit A. |last2=Pavlovski |first2=Blagoj |last3=Ademi |first3=Egzon |last4=Jashari |first4=Ahmed |last5=Boev |first5=Blazo |last6=Boev |first6=Ivan |last7=Makreski |first7=Petre |title=Effect Of Thermal Treatment Of Trepel At Temperature Range 800-1200˚C |journal=Open Chemistry |date=31 December 2019 |volume=17 |issue=1 |pages=1235–1243 |doi=10.1515/chem-2019-0132|doi-access=free }}</ref><ref>{{cite journal |last1=Reka |first1=Arianit |last2=Anovski |first2=Todor |last3=Bogoevski |first3=Slobodan |last4=Pavlovski |first4=Blagoj |last5=Boškovski |first5=Boško |title=Physical-chemical and mineralogical-petrographic examinations of diatomite from deposit near village of Rožden, Republic of Macedonia |journal=Geologica Macedonica |date=29 December 2014 |volume=28 |issue=2 |pages=121–126 |url=https://js.ugd.edu.mk/index.php/GEOLMAC/article/view/920}}</ref> It is also used in [[gas chromatography]] packed columns made with glass or metal as stationary phase.
== Composition ==
Each deposit of diatomaceous earth is different, with varying blends of pure diatomaceous earth combined with other natural clays and minerals.<ref name=":0" /> The diatoms in each deposit contain different amounts of silica, depending on the [[sedimentology|sedimentation conditions]], on the presence of other sediments (clay, sand, volcanic ashes), and on the age of the deposit ([[diagenesis]], [[silica]] (SiO<sub>2</sub>) dissolution/precipitation, diatoms tests ageing). The species of diatom may also differ among deposits. The species of diatom is dependent upon the age and [[paleoecology]] of the deposit. In turn, the shape of a diatom is determined by its species.
Many deposits throughout [[British Columbia]], such as Red Lake Earth, are from the [[Miocene]] epoch and contain a species of diatom known as ''Melosira granulata''. These diatoms have a small globular shape. A deposit containing diatoms from this epoch can provide certain benefits over others. For example, diatoms from the [[Eocene]] epoch are not as effective in their ability to absorb fluids because as older diatoms recrystallize, their small pores become filled with silica.<ref>{{cite web |title=Diatoms |url=https://www.ucl.ac.uk/GeolSci/micropal/diatom.html |publisher=UCL London's Global University |access-date=September 14, 2011}}</ref>
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