Of course, Mac is right. But I think that all too often, a cross on a chain is nothing more than an item of jewellery and that I find, rather trivialises the sacrifice of the cross.
Remember the old story about the jeweller who is asked for a chain with a cross and replies:
"Do you want a plain one or one with the funny little man on?"
What could make a better conversation opener than the 'tiny feet' badge of the SPUC organisation?
Or, if your employer refuses to allow the Christian cross to be worn, why not sport a Union Flag or the flag of St Patrick, St David and, even, St George?