adjective
BAD : It's a navy blue coat with golden buttons.
GOOD : It's a navy blue coat with gold buttons.
BAD : The purse contained six golden coins.
GOOD : The purse contained six gold coins.
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Golden is used in idiomatic expressions such as 'a golden opportunity', 'a golden handshake', 'a golden wedding anniversary', and in the phrase 'golden hair' (used mainly in literary styles).
To describe something that is made of gold or is the colour of gold, use gold : 'a gold bracelet', 'a black dress with red and gold stripes down the front'.