You can easily predict how wealthy a man is by simply looking at the engagement ring the fiancée carries.
In other words a ring is a simple representation of a man's pocket and in some cases it shows how deeply a man feels towards his women.
This myth of ring prediction runs among the poorest communities to the rich and famous in Hollywood.
In some African communities like in the republic democratic of Congo, the bigger the ring, the more gold it carries meaning the man is deeply in love with the women.
The same thing applies in Hollywood where the bigger the diamond, the wealthy the man is and the more appreciative the man is towards the women.
So if this is the case size really does matter.
Why is that a ring come in a circle shape? One of the main reasons for this is to fit on your finger also because in the Ancient Egypt, It was believe the circle shape of the ring symbolised fidelity and an unending love seeing that a rings has no starting point or ending point.
That is why engagement rings are used to represent or symbolise faithfulness and commitment of two people who are preparing to get married.
Rings are worn for different reasons:

• Engagement, this is when a man literally goes down on his knee and asks a women to marry.
  During this time the couples are known as engaged and not dating.
  
• Marriage, this is the dearest way of wearing a ring, because it symbolizes you belonging to one person only.
  Traditionally when one is wearing a wedding ring, they are often respected and not easily approached for any other type of intimate relationship as they are already committed and sharing their life with someone.
  
• Prestige, this is when women wears rings to show off how wealthy she is.
  In central African countries wealthy women often wears lots of jewelries, they are often seen with three to four rings on their fingers just to show how rich or wealthy they are, In most cases those show off rings are 24 carats of pure gold.
  One of the main reason for this is because there are lot of mines in Africa.
  
• Fashion, this has no age, no race, no gender, nor culture.
  Mostly it is worm for its beauty, esthetic and to follow the current trends.
  
• Social groups, "belonging" this is when a group of people share the same believe and decide to wear a ring as a common reminder for their believe this can be for a religious group, dance group chair leaders which is more like a friendship ring or tattoo artist I see them wearing rings which looks like a head of a skeleton.