John L. Moffat was born in Goshen, N.Y. in Feb., 1788. He lived in New York City until the mid-eighteen thirties. Then he moved to Northern Georgia and North Carolina where he had purchased gold mines. In his early years Moffat had learned to be a silversmith. While he was in Georgia, he became interested in assaying. Later, as a highly competent assayer and metallurgist, he returned to New York and became part of the firm of Wilmarth, Moffat & Curtis.

On June 21,1849 John Moffat, Joseph Curtis, Philo Perry, and Samuel Ward began advertising in San Francisco newspapers as Moffat & Co., Assayers. Robert Walker, the Secretary of Treasury, and Beebee, Ludlow & Co., the largest bullion dealer in the country recommended them. Moffat & Co. was in business for four years and had an excellent reputation throughout that time.

In July they began issuing rectangular ingots that ranged in denomination from $9.43 to $256.24. These were refined bullion but were used as money wherever gold dust was accepted by weight. In August they ten dollar coins later followed by five dollar ones. Albert Kuner was the die maker and chief engraver. He also made dies for other companies. Since Moffat & Co. always offered to redeem its coins with federal money at par, they always passed at face value. Their coinage was the only privately made California gold that was not discounted.

In 1850 and 1851 Moffat issued five dollar coins that were made from rusted and shattered dies. The coins have lumps and broken die surfaces. In the beginning of 1851, Moffat and Co. got a contract to make fifty dollar ingots for the United States Assay of Gold supervised by Augustus Humbert. In 1852 Moffat made ten dollar coins. They did this in response to a petition from local merchants. However, the Treasury Department disallowed Humbert’s request to issue these coins. Moffat retired from the firm that year and took a job with the San Joaquin Diving Bell Company. The last Moffat & Co. issue was a twenty dollar coin that appeared in 1853 at the same time the U.S. Assay Office was minting twenties too.

Moffat & Co. and the U.S. Assay Office closed on December 14, 1853. The new federal branch mint bought its equipment. Most of the coinage it made was melted for bullion to be recoined by the San Francisco Mint.

The rectangular ingots of 1849 varied in size and weight. The sixteen dollar piece was 35X15X3.8 millimeters. It weighed 28.28 grams or 20 ¾ carats, which was inscribed under MOFFAT & CO. with the denomination below.

The coins of 1849 and 1850 use the same design as the half eagles and eagles that the federal government was issuing at the time. The principal differences were the inscriptions. On Liberty’s coronet was inscribed MOFFAT & CO. and on the reverse S.M.V. (Standard Mint Value) CALIFORNIA GOLD with the denomination. The 1852 eagle had a redesigned reverse with the eagle facing right holding a serpent in its beak. It is inscribed 264 GRS. CALIFORNIA GOLD, 880 THOUS with the denomination below the eagle. The 1853 twenty dollar coin’s obverse is identical to the Liberty design except that MOFFAT & CO. appears on Miss Liberty's coronet. The reverse is also identical to the Liberty design except that across the top is SAN FRANCISCO CALIFORNIA.