Three of things...
Are you looking for one as a gift or to wear as an engagement ring for all eternity?
PK rings can be very fragile under certain circumstances so it may not be wise to wear one all the time.
I have never seen one in the style of a ladies engagement ring so it may need to be a special order. Try speaking to the guys at World Magic Shop in Birmingham or another dealer.
Oh, and congratulations on getting engaged.
