The Gold Bar is obtained from every Chest Block.
The gold bar is dropped by chest blocks. If touched, it yields 1 gold. After touching the bar, it disappears. The gold bar is currently unobtainable without a Chest Block (Excluding the Black Chest)
The gold bar cannot be added to your inventory, and thus cannot be placed down or removed without being destroyed by an obstacle or touched.
It is not recommended to risk your life for one gold, as you will possibly need to jump in the water to touch the dropped gold bar, and only lasts for 10 seconds before disappearing.