As a Ritual: 

You draw a circular arcane symbol on the ground with a 5ft diameter. You place the amount of gold you wish to reduce the weight on in the middle of the circle. You place the feather on top of the pile and wave your hands over the pile, concluding by blowing the feather off the top of the pile. The gold placed in the circle is made weightless but its other properties are not altered. *The chalk and feather are not consumed.

As an Action: 

You crack the chalk and feather in half over the gold that you intend to be weightless. The amount of gold turned weightless is a 5ft cube. *The chalk and feather are consumed.