There are various ways to check if your aquamarine is pure or not. Two of the best tests are: 1. Check the stone’s temperature: Aquamarine is a cold-temperature stone. If it is pure, sitting for a prolonged period in daylight would not impact its surface temperature, unlike glass which heats up quickly. 2. Check the stone’s transparency: Aquamarine is available in various colors, but one feature that distinguishes artificial from real is transparency. Pure aquamarine is transparent, while opaque or cloudy stones are likely fake.