Peridot
Only sold in olive-green.
The Peridot exists in contrast to most other gemstones only in one colour: olive-green.
The intensity of the green depends on the ferrous content in the mineral. Sometimes the cat-eye effect “Chatoyance” can appear caused by long, needlelike inclusions.
Peridot was already found in Pallasite meteorites and the largest ever cut stone (310 karat/62g) is on display in the Smithsonian Museum in Washington.