Olivine is a mafic mineral.
Like garnet it is
dense and dark, and it is rich in magnesium and iron.
Like garnet it forms
deep in Earth, under high pressures and temperatures.
It is actually a
so-called solid solution series, where one end is magnesium rich and
the ther is rich in iron.
It is a common mineral
in mafic rocks like gabbro, basalt, dunite and peridotite.
It is a very common mineral inside the Earth, and it alters easily.
It gets its name from
olive green colour, and is used as a gemstone, and in jewelry such as
in earrings and necklaces.