Creating Jewellery from glass is a very old technique. There are examples dating back to the ancient Egyptians. The careful controlled annealing and cooling creates a very strong material suitable for everyday wear and tear. It may be damaged if dropped on a hard surface but this also applies to many other things.
It is the nature of sterling silver to tarnish but silver cleaning cloths are readily availible and very effective. A anti-tarnish tab will be included in your purchase as well as a small gift bag.