This necklace seems to be made from simple thread, with a small sculpture of a stone pillar hanging from it.
A silver depiction of Rorym, Primarch of Satra, adorns the pillar, wrapping around the top.

Using an action, the sculpture can be enlarged up to 7ft long, or reduced back to its original size.
In this extended form, it can serve a multitude of purposes, such as a quarterstaff, or a support beam that can hold up to 1000 pounds.
The pillar shrinks back to its original size if the weight limit is exceeded.