Undetermined Role (unconfirmed)
Major Dunbar - a Southerner
Dr. Barry - Keene's Accomplice
Foster Merriman - Gem Collector
Martin - the Old Music Master
Thompson - Manager of the Alhambra Hotel
Rankin - Jewelers Association
Gordon Stanley - Bank President (as W.H. West)
Thomas Stone - a Diamond Salesman
Don Louis Gonzalez - a Wealthy Spaniard
Webster Deacon - Multi-Millionaire
Jared Fairfax - Eccentric Millionaire (as W.H. West)
Wayne - an Old Prospector
C.W. Fulton - a Western Millionaire
Harding - Wealthy Porcelain Collector
Dr. Perrin - the House Physician
Dr. Jardine - a Vivisectionist
George Duncan - a Traveling Man
Captain Bradshaw - Secret Service Agent
Harris' Father (as W.H. West)
Isaacson - a Diamond Broker
Prentiss - a Retired Banker
Dutch Hinkle - a Counterfeiter (as W.H. West)
James Sibley - Alice's Father
John Temple - a Circuit Rider
Judge Morton - Frank's Uncle
Dad Hallidy - Nellie's Father
Undetermined Role (unconfirmed)
Henry Van Dam - a Millionaire
Archibald Langdon - the Banker
Malva's Father (as William Herman West)
Angry Bear - the Indian Chief
Fealy - a Malpractitioner
Stelow - a Government Scout (as Wm. Herman West)
Harrison Grey - the Sociologist
Count Savanoff - a Russian Spy (as William Herman West)
William Sawyer - Helen's Father
Jacob Drake - Christine's Father - a Church Elder
William Cartwell - Wilfred's Father
Jack, a Settler (as William Herman West)
Simon Watson - a Drug Manufacturer
Ernest Conery, an Inventor
Gareta - a Notorious Bandit