帮忙翻译一篇英文文章Igneousrocksaregenerallyveryhard.becausetheyareformamoltenmassofrockmatercalledmagma.Themagma,whichcanbeseenonthesurfaceoftheEarthaslava,consistsofcomplexmixturesofchemicals.AsthemagmamovesthroughcracksintheEarth'ssurface,itcoolsaroundtheedges.ItmaycoolcompletelydeepwithintheEarth,oratthesurface.Thekindofigneousrockformeddependsonthecompositofthemagmaandtherateatwhichitcools.Oncooling,thechemicalsinthemagmaformcrystals.Thesecrystals,likegrainsofsaltorsuger,haveparticularshapesdependingontheirchemicalcomposition,andthelongerittakesthemtocool,thelargertheybecame.Thecolidcrystallineformsarecalledminerals.先打到这里吧后面太多了.