F=ρgV row = 2.94
Line V = 0.003 cubic meter
Description of the inscription on the crown V=V line = 0.0003 cubic meter.
The mass of crown M=49/9.8=5 kg.
Crown density = m/v = 5/0.003 =16.67x10.3kg/m3.
The density of gold is19.3x10.3kg/m3.
So it's not made of pure gold.