Can you send jewelry to another country as gift?(us to aus). No restrictions?

U.S. Postal yes. You do need fill out the declaration form. Value of item. Have reciet as to what you paid. Put a copy of that in with it. I am not sure if duty needs paid. Ask about that. Insure it.

Yes, but duty (taxes) will have to be paid based on the value in addition to the shipping charges

Yes, but the value will attract duty, and false declaration of value will mean penalty payments....

But it's not a good idea to use the postal service, except where the receiver has to sign of receipt

Y