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
Brazil, Madagascar, Mozambique, Pakistan, Russia, India, Sri Lanka, China, Color: blue to greenish blue, Hardness: 7.5, Refractive index: 1.57 1.59, Density: 2.67 2.75, Chemical composition: Be3Al2(SiO3)6, Crystal structure: hexagonal, Origins: Brazil, Nigeria, China. Aquamarine is a light blue or light greenish-blue variety of beryl, with darker stones being more expensive. Heat enhancement is often applied to enhance the blue color of aquamarines, but only clean pieces can be heated.