Gold

all that glitters is not gold

Meaning: the shining outer look of something is not a consistent sign of its real character

Example: My grandmother advised me to be careful about making new friends because all that glitters is not gold. Read on

silence is golden

Meaning: it is often better to say nothing at all

Example: Do not tell your mom that I broke her vase! Remember, silence is golden. Read on

kill the goose that lays the golden egg

Meaning: to destroy something that is profitable to you mostly because of greed.

Example: By selling off his business, Alex killed the goose that lays the golden egg. Read on

a golden key can open any door

Meaning: The prospect of receiving money will end up in getting any task accomplished.

Example: You should tip the reception staff to get a table sooner because a golden key can open any doors. Read on