L10 Igneous Rocks: Classification & Occurrence

Nucleation

Formation of stable start of lattice. Forms faster at lower temperatures although not too low

Growth

Growth of lattice. Forms faster at higher temperatures due to ease of diffusion

Course grained rock formation

formation due to slow cooling lots of growth with few nuclei

Fine grained rock formation

formation due to fast cooling with little growth and many nuclei

Glass or amorphous solid formation

formation due to very rapid cooling which means there is little growth and few formation of nuclei

Mafic

made up of magnesium and iron and is less then half silica

Intermediate

made up of just over half silica and a mixture

Felsic

made up of predominantly silica

Potassium Feldspar

sanidine microcline and orthoclase. same composition different structures

plagioclase

albite and anorthite. same structure different composition

gabbro

course grained mafic

basalt

fine grained mafic

diorite

course grained intermediate

andesite

fine grained intermediate

granite

course grained felsic

rhyolite

fine grained felsic