Making a compass pendant

I would like to make a metal casing for a small compass, about 1.5cm
diameter, to be used as a pendant. The compass will be used by
people who are in the process of designing their new house according
to passive solar design principles, ie having the living areas facing
north (southern hemisphere). It is really a gimmick to raise
awareness of the importance of using the sun’s direct energy to heat
your house in the winter, and avoid the heat from the sun in the
summer. These people will take their little compass, hanging around
their neck, to their prospective site and work out where to put the
various rooms of their new house.

I assume that a non-ferrous metal like silver would be OK and not
interfere with the movement of the compass needle. Am I right?

Any suggestions for design would be welcome.

Elizabeth Gordon-Mills
South Australia