Blue Topaz Versus Aquamarine Which Is More Expensive How Can I Tell Aquamarine From (blue) Topaz?

How can I tell aquamarine from (blue) topaz? - blue topaz versus aquamarine which is more expensive

I bought a pair of earrings from a jewelry store that is closed to the public. After the price is not fixed, which was kind of precious stones, were that the original price of approximately 270th Paid after 70% discount and 20% $ 67 extra. They have a very clear or colored light blue. All sales are final. I have a strange feeling that I cheated. How do I know if earrings aquamarine, blue topaz?