I-volcanic rock Pumice (eyaziwa kakhulu ngokuthi i-pumice noma i-poralt basous) iwuhlobo lwezinto ezisebenzayo zokuvikela imvelo. Kuyitshe eliyigugu eliyigugu elenziwa ngengilazi yentaba-mlilo, amaminerali namabhamuza ngemuva kokuqhuma kwentaba-mlilo. Itshe lentaba-mlilo liqukethe inqwaba yamaminerali nezinto ezilandelwayo, njenge-sodium, i-magnesium, i-aluminium, i-silicon, i-calcium, i-titanium, i-manganese, i-iron, i-nickel, i-cobalt ne-molybdenum. Ine-wave infrared magnetic ngaphandle kwemisebe, Ngemuva kwezinkulungwane zeminyaka, abantu bathole inani layo ngokuya ngokuya. Manje sekunwetshiwe emikhakheni yokwakha, okongiwa kwamanzi, ukugaya, okokuhlunga, okosa izoso, ukulungisa ingadi, ukulima okungenanhlabathi, imikhiqizo yokuhlobisa njalonjalo. Idlala indima engabuyiseki kuyo yonke imikhakha yokuphila! I-rock eshisayo ebhaka emuva luhlobo lwezokwelapha ngamatshe, olusebenzisa amatshe ashubile entaba-mlilo ukumunca amandla amabi omzimba womuntu, isize umzimba womuntu uqede ubuthi futhi ukhuthaze umzimba womuntu.