Brazil, Southern and central Africa, Madagascar, Color: yellow, Hardness: 7, Refractive index: 1.54 1.55, Density: 2.65 2.66, Chemical composition: SiO2, Crystal structure: hexagonal, Origins: Widespread; best stones come from Brazil. Citrine is one of the least expensive gemstones. Even very big pieces, 50 carats and more, can be easily found on the market. Greenish-yellow and orange stones are more valuable, and heat treatment is often applied to enhance the yellow color., Yellow, brown
Russia, Southern and central Africa, Color: green, yellowish green, Hardness: 6.5, Refractive index: 1.88 1.89, Density: 3.82 3.85, Chemical composition: Ca3Fe2(SiO4)3, Crystal structure: isometric, Origins: Russia, Namibia