Minerals (Category B)
Fayalite is the iron rich end-member of the olivine solid-solution series.
Fayalite is from olivine group and it is one of the two minerals that are simply called olivine. The other mineral is known as forsterite. The mineral is named for the Island of Fayal of the Azores.
Fayalite is found in the ultramafic igneous rocks. Olivine minerals have a high melting point and it crystallizes first from a mafic magma. This is due to the molten lava already contain crystallized grains of olivine.
Fayalite is sometimes also found in many iron-nickel meteorites. It is found in significant size and somtimes even occupying over 50% of the meteorites. Slices cut very thin from these meteorites are extremely attractive with polished steel gray of the iron and the embedded grains of gemmy green olivine. This effect even produces a very close mineral being equivalent to stained glass artwork.