This is the first of two episodes depicting this event. The other one is The Great Diamond Mines (1968). Maverick episode Diamond in the Rough (1958) also used this incident for its story line.
According to Asbury Harpending's autobiography, the cable from San Francisco to London did cost $1100 (over $21,000 in 2018). In the cable, William Ralston, founder of the Bank of California, estimates the find to be worth at least $50,000,000 (nearly $1 billion in 2018).