Aquamarine

The blue-colored gemstone of the Beryl group, Aquamarine is the most popular blue color gemstone in today's market. However, it lacks sapphire’s blue, it has its own market in today's time. The finest aquamarines have a moderately strong, medium-dark blue to slightly greenish blue. Iron causes the blue color in aquamarine.

Aquamarine is generally mined in Brazil, Pakistan, China, Kenya, the US, and many more. The introduction of blue topaz had a negative impact on the demand for aquamarine as it was its perfect imitator. 
Generally, all aquamarines are heat treated. Heat treatment removes the yellow color from it and produces a brilliant greenish-blue color.