Hi Cindy,
There is some truth to what the salesgirl was telling you, but in my opinion, it seems like if you really want an aquamarine stone...then you should go for it.
The MOHS scale was formulated in the 1800's by a German mineralogist (Geologist) named Friedrich Mohs. As a Geologist, he spent over a decade studying and experimenting with various minerals and gemstones. Friedrich Mohs created an easy to remember scale by which one could easily discover if a mineral was delicate or hard.
As a rule, if your gem does not measure at least 7 on the MOHS scale, it is a delicate stone and can be damaged very easily. So extra care should be taken while wearing these ornaments. An aquamarine stone weighs in at a 7.5. A stone such as a pearl...is much more delicate...weighing in at around a 3 to a 4
For everyday wear, Diamonds are the best - their hardness is 10 and they do not get scratched easily. Rubies, Emeralds and sapphires also are great for people with active lifestyles since they measure 9 on the MOHS scale and have a greater resistance.
So to sum it up, an aquamarine stone is fairly sturdy...but not as durable as other stones out there.
