peridot is gem-quality olivine and a silicate mineral. its green color is affiliate on the iron contents within the structure of the gem. the molecular structure of peridot consist of isomorphic olivine, silicate, magnesium and iron in an orthorhombic crystal system.
garnets are a category of silicate minerals that have been used since the Bronze Age as gemstones and abrasives. all species of garnets possess similar physical properties and crystal forms, but differ in chemical composition.