According to the site CoinFacts.com, the nominal weight of an uncirculated St. Gaudens $20 coin is 33.4 grams.
A 1924 Saint-Gaudens $20 gold coin weighs 33.436 grams and of that weight, gold comprises 30.092 grams.
assuming you are referring to the $20 coin, it was called a Saint Gaudens
These are beautiful coins - a 1924 Saint-Gaudens $20 Double Eagle coin is worth in extra fine condition (EF40): $1225.
There is 0.9675 Troy ounces of pure gold in a $20 St. Gaudens.
2.79mm is the nominal thickness of the 1924 Saint-Gaudens $20.00 double eagle.
Assuming no mint mark retail values run from $1,370.00-$1,570.00 for circulated coins.
If you are in possession of a 1924 Saint-Gaudens $20 Double Eagle gold coin, its value in extra-fine condition (EF-40) is: $1225.00.
A 1923 $20 Gold Coin - aka - Saint-Gaudens Double Eagle - in a mint state of MS63 is worth: $1500.
The 1933 Gold Double Eagle coin, designed by Augustus Saint-Gaudens, sold for $7.5 million in 2002, the highest price in the world ever paid for a coin.
When new, these coins weighed 33.4 grams. 10% of that was copper, so the weight of pure gold is 0.9 * 33.4 = 30.06 gm
$20
Values depending on grade for circulated 1915 Saint-Gaudens are $1,340.00-$1,710.00 uncirculated examples start at $1,770.00