There are 15.54 grains in one gram and there are exactly 31.1034768 grams in one troy ounce of gold.
So the 6 grains they found in a 1.5kg sample equals 2.59 grams of gold. You would need about 72 grains to equal 1 troy ounce of gold.
Put another way you would need to process approx 18kg of material to find one ounce of gold worth about $1,300. Not bad at all.
