1950's rhinestone necklace. The array of baguette and marquise stones make me think of frost crystals. Each stone is sparkling and clear.
The necklace is adjustable, and the wearable length is up to about 15 1/4", maximum. The clasp is a simple hook, which looks backward, but is designed so that the prong faces away from your neck. This was a common clasp for 50's necklaces. It is possible to add a bit of silver-tone chain to give you another inch or two - please ask for details.