Please oblige me for a moment. Aquamarine is my birthstone. I very much wanted a birthstone ring as a young girl, and in 4th grade, my mom and dad allowed me to select one for my birthday. I remember shopping with my mother at the Hess & Culbertson store at Crestwood Plaza, on the corner of the mall next to Stix, Baer & Fuller. (If it was Jaccard's, then forgive my memory.) The gentleman behind the counter showed me a ring with four oval, faceted aquamarines set in a diamond pattern, which was a bit much, considering I was turning 10.
We ended up buying my ring at J.C. Penney at West County Center. It was an oval, set in a bezel. I wore it proudly until one day on the playground at school I was playing "Miss Mary Mack, Mack, Mack, all dressed in black, black, black . . . " against the wall of the building. I was slapping my hands on the bricks when I realized that my ring had spun around on my finger, and now the entire top of the stone was abraded. It was ruined. A few years later, when I received a charm bracelet, I added it as a charm. It's still there today.
I wish someone had told me how to properly care for my ring when we bought it. That's a lesson I have always taken to heart, and when I work with clients, informing them of proper care is an important component of the purchase. But I digress.
Aquamarines have a hardness of 7.5. They are the blue-green coloration of the mineral beryl. Fun fact: when beryl is a deep saturated green color, it is an emerald. When it is of pink coloration, it is Morganite. Aquamarine rings can be worn every day, but shouldn't be on the hand when doing laundry, lifting weights, or gardening.
What's the difference between aquamarines and blue topaz? First, they are two different minerals. Even though some may possess similar colorations, one is beryl and one is topaz. Aquamarines are usually greenish in color when found in nature. They are heated, which permanently changes the color to a bluer tone. Blue topaz is created from colorless topaz by nuclear irradiation. First, the colorless material is irradiated, which turns the stone brown or brownish-green. Then this material is heated so that it hopefully turns blue. Virtually no blue topaz exists in nature. The irradiation process is also considered permanent and stable. Topaz is a bit more durable than aquamarine, with a hardness of 8.0.
Aquamarines are much more rare than blue topaz, and hence more valuable. As a gemologist, I would never decide at a glance whether a blue-green gemstone was one or the other. There are several gemological instruments that can be employed to make that determination, starting with a loupe, a refractometer, specific gravity liquids, etc.
Aquamarines are believed to give their wearers courage and happiness. In the Middle Ages it was though to reduce the effects of poisons. I'm not sure about that, but I do know that if you're wearing an aquamarine ring, don't slap your hand against a brick wall!