Ah...the wedding ring. Many of our traditions concerning this symbol and token began in ancient Egypt.
The ring is a circle - the symbol of eternity. Never ending, always moving. The shape of things far away...the sun and the moon.
But it's not just the "ring," the hole in the center where your finger goes carries the symbolism of a gateway. Your finger going through that ring symbolizes an entrance to a new life, changes, opportunities and sorrows, known and unknown - but together.
Even the finger symbolized love. The Egyptians believed that the vein in the third finger on the left hand flowed directly from the heart. The Romans adopted this, calling that vein the "vena amoris" - the vein of love.
The first people who wore wedding rings made them out of hemp or some other kind of fiber...so the love might have been eternal...the ring, not so much.
Later, people used bone, onyx, or other easily carved stone. It was not until coinage became easily "mintable", that metal rings became more common.
(Note: when silver was popular during the renaissance in Italy, engagement (or betrothal) rings also became popular. The wedding ring was added to the engagement ring; the engagement ring was made of silver and replaced with an identical (gold) ring during the wedding ceremony.)
For a time, in Ireland, people considered it bad luck for a wedding ring to be made from anything other than gold (the poor, prohibited by cost from wearing gold, would have considered themselves prohibited by superstition from wearing anything but gold -- stayed ring-less?). The Church of England put a stop to that, teaching that the material didn't matter, as long as a ring was present.
Contrast that with the Puritans, who believed that any jewelry, including a wedding ring was both vanity and pagan, hardening back to the Egyptian root on the practice, and banned the wearing of wedding rings. This practice stuck: an old friend of mine told that her parents had been brought up in a Pilgrim Holiness church. They were a scandal, since her mom wore a wedding ring.
Millennia later, the wedding ring remains a symbol of love and eternity; so much that the exchange of rings is part of most wedding vows
With this ring, I thee wed...