This is an unusually large antique'pool of light' rock crystal pendant. In the form of a drop, rather than the usual sphere, it has a silver cup setting with a scalloped edge (unmarked, tests as sterling).
In very good condition, there is a small scratch (please see pics) which is only noticeable on close inspection and can probably be polished out. Under a loupe some tiny crystalline inclusions are visible in the crystal in a couple of places.2.9cm long excluding bail loop, 1.8cm at the widest point. Probably very early 20th century.
A stunning example of a'pool of light' pendant in an unusual shape.