According to the author of the book of Ezra, these items were very special gifts made of gold and shiny copper, showing how important they were to God's people. These treasures were precious and valuable, meant for God's house.
Ezra 8:27: Also twenty basons of gold, of a thousand drams; and two vessels of fine copper, precious as gold. [fine...: Heb. yellow, or, shining brass] [precious: Heb. desirable]
This verse commands not to make gods of silver or gold, which contrasts with the mention of rich materials in Ezra 8:27.
Exodus 20:23: Ye shall not make with me gods of silver, neither shall ye make unto you gods of gold.