How Does Aquamarine Form?

aquamarine-form Credit: Jim H./CC-BY 2.0

Aquamarine forms when magma under the Earth's crust interacts with mineral-rich rocks under mountain ranges. The magma cools as it enters fissures and crevasses of rocks called pegamites. The minerals in the pegamites heat up when they interact with the magma, forming the gemstone.

Pegamites are a type of rock that is formed primarily of mineral crystals. Almost all aquamarines are formed in pegamites. Aquamarine is a type of mineral called beryl. Beryl can be many colors, but when it is blue or blue-green, it is called aquamarine. Another common gemstone with beryl composition is morganite, which is pink. The color the beryl takes depends on the minerals it interacts with. Aquamarine is a combination of beryllium and aluminum silicate.

Aquamarine can be found in many places around the world where there are mountain ranges. It is mined in Africa, India, South America, Russia and North America. The quality of aquamarine depends primarily on its color. The gem is more valuable the deeper the blue-green color. Most aquamarine jewelry has lighter-colored stones. Other rare aquamarines have a cat's-eye effect, which is a line of shimmering light that can be viewed from different angles. Unlike many gemstones, most aquamarines are flawless, making them a good choice for rings and pendants.