Pumice ko pumice wani nau’in dutse ne mai haske mai launi, ya ƙunshi kumfa da aka yi da kumfa mai bangon gilashi , kuma galibi ana kiranta da gilashin dutsen dutsen silicate.
Wadannan duwatsun suna samuwa ne ta magma acidic ta hanyar tashin wuta da ke fitar da abubuwa cikin iska; sannan a yi jigilar kaya a kwance kuma a taru azaman dutsen pyroclastic.
Pumice yana da manyan kaddarorin sinadarai, yana ƙunshe da adadi mai yawa na sel (tsarin salula) saboda faɗaɗa kumfa na iskar gas ɗin da ke cikinta, kuma galibi ana samun su azaman sako-sako da abu ko gutsuttsura a cikin breccia mai aman wuta. Yayin da ma’adanai da ke cikin pumice sune feldspar, quartz, obsidian, cristobalite, da tridymite.
Pumice yana faruwa ne lokacin da magma acidic ya tashi sama kuma ba zato ba tsammani ya haɗu da iska ta waje. Kumfa na gilashin halitta tare da / gas ɗin da ke cikinsa yana da damar tserewa kuma magma ya daskare ba zato ba tsammani, pumice gabaɗaya yana wanzuwa azaman gutsuttsuran ɓarke da ake fitarwa yayin fashewar volcanic masu girma daga tsakuwa zuwa duwatsu.
Pumice yawanci yana faruwa azaman narke ko gudu, sako-sako da abu ko gutsuttsura a cikin breccias mai aman wuta.
Hakanan ana iya yin Pumice ta hanyar dumama obsidian, ta yadda iskar gas ke tserewa. Dumama da aka yi akan obsidian daga Krakatoa, zafin da ake buƙata don canza obsidian zuwa pumice ya kai 880oC. Matsakaicin nauyin obsidian wanda asalinsa 2.36 ya ragu zuwa 0.416 bayan jiyya, don haka yana yawo a cikin ruwa. Wannan dutsen dutse yana da kaddarorin hydraulic.
Pumice fari ne zuwa launin toka, ruwan rawaya zuwa ja, rubutun vesicular tare da girman bango, wanda ya bambanta dangane da juna ko a’a ga tsari mai ƙonawa tare da madaidaiciyar kai.
Wani lokaci ramin yana cika da zeolite/calcite. Wannan dutse yana da juriya ga daskarewa raɓa (sanyi), ba don haka hygroscopic (ruwa tsotsa). Yana da ƙarancin canja wurin zafi. Ƙarfin matsi tsakanin 30 – 20 kg / cm2. Babban abun da ke ciki na amorphous silicate ma’adanai.
Dangane da hanyar samuwar (zuwa wuri), rarraba girman barbashi (gutsi) da kayan asali, adibas ɗin pumice ana rarraba su kamar haka:
Yankin yanki
Mai ruwa-ruwa
Sabon ardante; watau adibas da aka samu ta hanyar fitowar iskar gas a kwance a cikin lava, wanda ke haifar da cakuda gutsuttsura masu girma dabam a cikin sigar matrix.
Sakamako na sake-ajiye (sabon ajiya)
Daga metamorphosis, yankunan da ke da ɗanɗano mai aman wuta ne kawai za su sami ma’adinan tsiro na tattalin arziki. Shekarun yanayin ƙasa na waɗannan adibas yana tsakanin Sakandare da na yanzu. Volcanoes da ke aiki a lokacin wannan zamani na ilimin ƙasa sun haɗa da iyakar Tekun Pasifik da hanyar da ta tashi daga Tekun Bahar Rum zuwa Himalayas sannan zuwa Gabashin Indiya.
Duwatsu masu kama da sauran ƙamshina ne da dutsen dutse da dutsen dutse. Pumicite yana da nau’in sinadarai iri ɗaya, asalin samuwar da tsarin gilashi kamar pumice. Bambancin shine kawai a cikin girman barbashi, wanda bai wuce inci 16 a diamita ba. Ana samun Pumice kusa da wurin da aka samo shi, yayin da iska ta yi jigilar pumicite zuwa wani wuri mai nisa, kuma an adana shi a cikin nau’in tarin toka mai kyau ko kuma a matsayin laka.
Dutsen dutsen dutsen mai aman wuta yana da ja-ja-ja-ja-ja-ja-ja-ja-ja-ja-ja-jaja-bak’i, wadanda aka ajiye a lokacin fashewar dutsen basaltic daga fashewar aman wuta. Yawancin ma’adinan cinder ana samun su azaman gutsuttsuran gadon gado masu tsayi daga inch 1 zuwa inci da yawa a diamita.
Yiwuwar Pumice na Indonesiya
A Indonesiya, kasancewar tsaunuka koyaushe ana danganta shi da jerin tsaunukan Quaternary zuwa na uku. Rarraba ta ya shafi yankunan Serang da Sukabumi (Yammacin Java), tsibirin Lombok (NTB) da tsibirin Ternate (Maluku).
Yiwuwar ajiyar kuɗaɗen da ke da mahimmancin tattalin arziƙi da tanadi mai yawa suna kan tsibirin Lombok, West Nusa Tenggara, tsibirin Ternate, Maluku. Adadin da aka auna a yankin an kiyasta fiye da tan miliyan 10. A yankin Lombok kuma, an fara yin amfani da nama ne tun shekaru biyar da suka gabata, yayin da a Ternate aka yi amfani da shi a shekarar 1991 kawai.