Talc
Talc is translucent to opaque, with colors ranging from whitish grey to green with a vitreous and pearly luster.[8] Talc dominantly forms from the metamorphism of magnesian minerals such as serpentine, pyroxene, amphibole, and olivine, in the presence of carbon dioxide and water.The trioctahedral sheet has an equal positive charge, since its bulk composition is Mg3(OH)24+ The combined TOT layer thus is electrically neutral.Extraction in disputed areas of Nangarhar province, Afghanistan, has led the international monitoring group Global Witness to declare talc a conflict resource, as the profits are used to fund armed confrontation between the Taliban and Islamic State.[16] Talc is used in many industries, including paper making, plastic, paint and coatings (e.g. for metal casting molds), rubber, food, electric cable, pharmaceuticals, cosmetics, and ceramics.In finely ground form, talc finds use as a cosmetic (talcum powder), as a lubricant, and as a filler in paper manufacture.The American Academy of Pediatrics recommends that parents avoid using baby powder because it poses a risk of respiratory problems, including breathing trouble and serious lung damage if inhaled.[21] Talc is used in the production of the materials that are widely used in the building interiors such as base content paints in wall coatings.This can be helpful as a cancer treatment to prevent pleural effusions (an abnormal collection of fluid in the space between the lungs and the thoracic wall).[31] In contrast, however, research published in 1995 and 2000 concluded that, although it was plausible that talc could cause ovarian cancer, no conclusive evidence had been shown.[32][33] Further, a 2008 European Journal of Cancer Prevention review of ovarian cancer and talc use studies pointed out that, although many of them examined the duration, frequency, and accumulation of hygienic talc use, few found a positive association among these factors and some found a negative one: “It may be argued that the overall null findings associated with talc-dusted diaphragms and condom use is more convincing evidence for a lack of a carcinogenic effect, especially given the lack of an established correlation between perineal dusting frequency and ovarian tissue talc concentrations and the lack of a consistent dose-response relationship with ovarian cancer risk."Instead, the authors credited powdered talc with "a high degree of safety.”[34] Similarly, in a 2014 article published in a leading cancer journal, the Journal of the National Cancer Institute, researchers reported the results of a survey of 61,576 postmenopausal women, more than half of whom had used talc powder perineally.[38] The United States Food and Drug Administration considers talc (magnesium silicate) generally recognized as safe (GRAS) to use as an anticaking agent in table salt in concentrations smaller than 2%.[47] In 2006 the International Agency for Research on Cancer classified talcum powder as a possible human carcinogen if used in the female genital area.[50] In October 2016, a St. Louis jury awarded $70.1 million to a Californian woman with ovarian cancer who had used Johnson's Baby Powder for 45 years.The judge stated that Echeverria proved there is "an ongoing debate in the scientific and medical community about whether talc more probably than not causes ovarian cancer and thus (gives) rise to a duty to warn", but not enough to sustain the jury's imposition of liability against Johnson & Johnson stated, and concluded that Echeverria did not adequately establish that talc causes ovarian cancer.In 2023 J&J proposed a nearly $9bn settlement with 50,000 claimants saying the claims were "specious" but it wanted to move on from the issue, but judges blocked the plans, ruling that the subsidiary was not in financial distress and could not use the bankruptcy system to resolve the lawsuits.[57] In July 2023 J&J sued researchers who linked talc to cancer alleging they used junk science to disparage company's products, while defendants say the lawsuits are meant to silence scientists.
Talcum (disambiguation)synthetic magnesium silicateforsteriteSilicate mineralFormulaIMA symbolStrunz classificationCrystal systemMonoclinictriclinicCrystal classSpace groupLight to dark greenCrystal habitCleavagebasal cleavageFractureTenacitySectileMohs scaleLusterStreakDiaphaneitySpecific gravityRefractive indexBirefringencePleochroismUltravioletfluorescenceclay mineralcomposedhydratedmagnesiumsilicatechemical formulacorn starchbaby powderthickening agentlubricantceramicspaintsroofing materialcosmeticsfoliatedfibrouscrystalscratchhardness comparisonstreak platemineral acidsSoapstonemetamorphic rockPersianseleniteserpentinepyroxeneamphiboleolivinetalc carbonatescarbon dioxidemagnesiteskarnificationdolomitesilicacalciteblueschisteclogitemetamorphic reactionchloritequartzkyanitekerolitesepiolitestevensitealuminiumphengitegarnetglaucophanewhiteschistpyrophyllitevan der Waals forcesbruciteultramafic rocksterranesMusgrave BlockorogensHimalayasPakistanBhutanTalc carbonateArchaeancratonskomatiiteYilgarn CratonWestern AustraliaLachlan Fold BeltAustraliaBrazilGuiana ShieldophioliteTurkeyMiddle EastLuzenac GroupLuzenacNangarhar provinceGlobal Witnessconflict resourceTalibanIslamic Stateplasticsteatitecosmeticastringentdiaper rashAmerican Academy of PediatricsZinc oxideweldingmetalworkingfood additiveglidantpleurodesispleural effusionpneumothoraxEuropean Unionadditive numbercrazing