talc | Definition, Uses, & Facts - Encyclopedia Britannica

talc, common silicate mineral that is distinguished from almost all other minerals by its extreme softness (it has the lowest rating [1] on the Mohs scale ... talc TableofContents talc Introduction FastFacts RelatedContent Quizzes Media Images More MoreArticlesOnThisTopic Contributors ArticleHistory Home Science EarthScience,GeologicTime&Fossils EarthSciences talc mineral Actions Cite verifiedCite Whileeveryefforthasbeenmadetofollowcitationstylerules,theremaybesomediscrepancies. Pleaserefertotheappropriatestylemanualorothersourcesifyouhaveanyquestions. SelectCitationStyle MLA APA ChicagoManualofStyle CopyCitation Share Share Sharetosocialmedia Facebook Twitter URL https://www.britannica.com/science/talc GiveFeedback ExternalWebsites Feedback Corrections?Updates?Omissions?Letusknowifyouhavesuggestionstoimprovethisarticle(requireslogin). FeedbackType Selectatype(Required) FactualCorrection Spelling/GrammarCorrection LinkCorrection AdditionalInformation Other YourFeedback SubmitFeedback Thankyouforyourfeedback Oureditorswillreviewwhatyou’vesubmittedanddeterminewhethertorevisethearticle. JoinBritannica'sPublishingPartnerProgramandourcommunityofexpertstogainaglobalaudienceforyourwork! ExternalWebsites TheUniversityofAuckland,NewZealand-Geology-RocksandMinerals-Talc BritannicaWebsites ArticlesfromBritannicaEncyclopediasforelementaryandhighschoolstudents. talc-StudentEncyclopedia(Ages11andup) Print Cite verifiedCite Whileeveryefforthasbeenmadetofollowcitationstylerules,theremaybesomediscrepancies. Pleaserefertotheappropriatestylemanualorothersourcesifyouhaveanyquestions. SelectCitationStyle MLA APA ChicagoManualofStyle CopyCitation Share Share Sharetosocialmedia Facebook Twitter URL https://www.britannica.com/science/talc Feedback ExternalWebsites Feedback Corrections?Updates?Omissions?Letusknowifyouhavesuggestionstoimprovethisarticle(requireslogin). FeedbackType Selectatype(Required) FactualCorrection Spelling/GrammarCorrection LinkCorrection AdditionalInformation Other YourFeedback SubmitFeedback Thankyouforyourfeedback Oureditorswillreviewwhatyou’vesubmittedanddeterminewhethertorevisethearticle. JoinBritannica'sPublishingPartnerProgramandourcommunityofexpertstogainaglobalaudienceforyourwork! ExternalWebsites TheUniversityofAuckland,NewZealand-Geology-RocksandMinerals-Talc BritannicaWebsites ArticlesfromBritannicaEncyclopediasforelementaryandhighschoolstudents. talc-StudentEncyclopedia(Ages11andup) By TheEditorsofEncyclopaediaBritannica • EditHistory TableofContents talc Seeallmedia RelatedTopics: phyllosilicate steatite minnesotaite soapstone ...(Showmore) Seeallrelatedcontent→ talc,commonsilicatemineralthatisdistinguishedfromalmostallothermineralsbyitsextremesoftness(ithasthelowestrating[1]ontheMohsscaleofhardness).Itssoapyorgreasyfeelaccountsforthenamesoapstonegiventocompactaggregatesoftalcandotherrock-formingminerals.Denseaggregatesofhigh-puritytalcarecalledsteatite.Sinceancienttimes,soapstoneshavebeenemployedforcarvings,ornaments,andutensils;Assyriancylinderseals,Egyptianscarabs,andChinesestatuaryarenotableexamples.Soapstonesareresistanttomostreagentsandtomoderateheat;thus,theyareespeciallysuitableforsinksandcountertops.Talcisalsousedinlubricants,leatherdressings,toiletanddustingpowders,andcertainmarkingpencils.Itisusedasafillerinceramics,paint,paper,roofingmaterials,plastic,andrubber;asacarrierininsecticides;andasamildabrasiveinthepolishingofcerealgrainssuchasriceandcorn. BritannicaQuiz (Bed)Rocksand(Flint)Stones Diamondsmaybeagirl’sbestfriend,butwhatisthatmineral’sclosestrelative?Testyourknowledgeofrocks,minerals,andallthings"yabbadabbadoo"inthisquiz. Talcisfoundasametamorphicmineralinveins,infoliatedmasses,andincertainrocks.Itisoftenassociatedwithserpentine,tremolite,forsterite,andalmostalwayswithcarbonates(calcite,dolomite,ormagnesite)inthelowermetamorphicfacies.Italsooccursasanalterationproduct,asfromtremoliteorforsterite. Oneoftheremarkablefeaturesoftalcisitssimple,almostconstantcomposition;talcisabasicmagnesiumsilicate,Mg3Si4O10(OH)2.Unlikeothersilicates,evencloselyrelatedones,talcappearstobeunabletoacceptironoraluminumintoitsstructuretoformchemical-replacementseries,eventhoughanironanalogoftalcisknown,andthestructurallyrelatedchloriteformsatleastapartialseriesbetweenironandmagnesiumend-members.Talcisdistinguishablefrompyrophyllitechemicallyandoptically. GetaBritannicaPremiumsubscriptionandgainaccesstoexclusivecontent. SubscribeNow TheEditorsofEncyclopaediaBritannica ThisarticlewasmostrecentlyrevisedandupdatedbyAdamAugustyn.