Peridot Jewelry

Where the name comes from: Uncertain, possibly from Anglo-Norman pedoretes.
Where the stones come from: Peirdot is a form of olivine itself quite common, gem quality is rare however., the USA, Australia, Brazil, China, Pakistan and several places in Africa produce peridot.
Chemistry: Magnesium iron silicate, (Mg,Fe)₂SiO₄  the greenness depends on additional traces of iron.
Colors: Shades of green of varied intensity, from yellowish through lime and emerald to brownish. Dark olive-green is the most valued.
...and another thing:  Peridot has been found in meteorites.

Prices correct at time of writing - subject to change