Aquamarine is a relatively common gemstone, and is affordable in lighter colors. Deeper colors can command high prices. Some enormous transparent crystal masses of Aquamarine have been found, and exquisite gems weighing thousands of carats have been cut from them. The light blue to blue-green color of Aquamarine may fade upon prolonged exposure to light, so it is especially important to purchase this gem from a reliable dealer. Aquamarine is a hard and durable gem, but it may develop internal cracks if banged hard. Light blue Topaz is easily mistaken for Aquamarine. The colors of these two gems can be identical, and their physical properties are very similar. Topaz is generally less expensive, and some fraudulent dealers may sell their Topaz as Aquamarine. Unlike Emerald, Aquamarine gems are often completely flawless. Aquamarines with visible flaws are rarely seen. The costs of producing synthetic Aquamarine are very high when compared to the relative abundance of this gem, so synthetic Aquamarine is generally not produced for the gemstone market.