http://ianlafo.com/scale-gold/
Scale Gold
How I can know if my bar of gold is real? The bar, said 37.5 grams of 24K, but only weighs 18 to 19 grams on the scale
The gold bar says 9999 is Hong Kong fine gold weight 37.5 grams. The scale is just 18-19 grams.
Take it to the nearest jewelers, who will be able tell you, I would say that whoever sold it to you ripped out, was a purchase on eBay? Hope this helps!