Each month, based on the number of Golden Coins played, you will reach a specific tier. You will keep your status all month long, plus 2 consecutive months afterwards, so you can enjoy your rewards for longer time. If during this time, you qualify for a higher tier, you will automatically be upgraded, so you can enjoy the higher benefits straight away.
If during this time, you will not play at the level to keep your current tier, you will be downgraded a level.
Once you reach Ruby, Diamond or Black Diamond tiers, you will be keeping this tier for the whole calendar year and the next 3 months for the next year.