The Assay Office of G.W. Bell, established in 1859, was located in Parrott's Iron Building on California Street, one door west of Montgomery, in San Francisco. Trade directory advertisements noted that "Gold Dust, Ores & Minerals of Every Description Assayed. Returns Made at the Usual Rate of Commission with Correctness and Dispatch. For the convenience of Parties desiring Bars early on Steamer Days, Deposits will be received on arrival of the Expresses of the Evening previous," and "Having a complete CHEMICAL LABORATORY in connection with my facilities for Melting and Assaying, I feel confident of being able to give complete satisfaction to all who may favor me with their patronage."

On April 16, 1866, the Daily Evening Bulletin ran an article, "Terrible Calamity" on page 5, which noted, in part:

One of the most terrible calamities that ever occurred in San Francisco — explosions so powerful as to shake the earth like an earthquake — caused by combustion of a case of nitro glycerine which had been brought to Wells Fargo...Mr. Bell was in the act of taking a horse from the stable to the rear of the building.

And, so, he met his demise.

In 1867 the Pacific Coast Directory noted that the firm of Rogers & Brown, Assayers, was the successor to G.W. Bell and was located in the same office.