My dad is part Irish/ Scottish and so both my parents' wedding rings are plain white-gold Claddagh rings. Also, fun fact: Supposedly if the hands are holding a heart pointing outwards, it signifies looking for love, and likewise pointing inwards has found love.
It also depends on the hand. On the right hand, pointing outward is single. Inward is in a relationship.
On the left hand outward is engaged and Inward is married.
Promise rings/purity rings don't have to have any religious symbol on them, though. Mine is just three small diamonds (representing the Holy Trinity) put together in the form of a heart between two diamond-studded vines. However, if you didn't know that the three diamonds represent the Holy Trinity, then to you it'd just look like some pretty ring. Just wanted to mention it in case you see some thirteen-year-old with a purity ring and assume that it's an engagement ring just because of its design.
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On the left hand outward is engaged and Inward is married.